text: Title: Project dependencies may have API risk issues
  Body: Hi, In **flasgger**, inappropriate dependency versioning constraints can cause risks.
  
  Below are the dependencies and version constraints that the project is using
  ```
  Flask>=0.10
  PyYAML>=3.0
  jsonschema>=3.0.1
  six>=1.10.0
  mistune*
  werkzeug*
  ```
  
  The version constraint **==** will introduce the risk of dependency conflicts because the scope of dependencies is too strict.
  The version constraint **No Upper Bound** and **\*** will introduce the risk of the missing API Error because the latest version of the dependencies may remove some APIs.
  
  After further analysis, in this project,
  The version constraint of dependency **Flask** can be changed to *>=0.10,<=0.12.5*.
  
  The above modification suggestions can reduce the dependency conflicts as much as possible, 
  and introduce the latest version as much as possible without calling Error in the projects.
  
  The invocation of the current project includes all the following methods.
  
  <details>
  <summary>The calling methods from the Flask</summary>
  <pre>
  json.dumps
  json.loads
  json.dump
  </pre>
  </details>
      
  <details>
  <summary>The calling methods from the  all methods</summary>
  <pre>
  value.split
  rule.methods.difference
  parameter.get
  content.values
  full_doc.replace
  wraps
  schema.get.lower
  schema.items
  is_python_file
  APISpecsView.as_view
  re.compile
  specs_data.get
  OneOf
  self.get_apispecs
  mapping.items
  read
  parsed_data.items
  app.run
  request.endpoint.lower
  self.endpoints.append
  operations.items
  self.load
  spec.get.get
  swag.keys
  get_specs
  Response
  k.startswith
  resolve_path
  verb.lower
  Api
  rule.endpoint.replace
  regex.search
  __file__.os.path.dirname.root_path.swag_path.replace.split
  deepcopy
  self._init_config
  reqparse.RequestParser
  Swagger
  user.password.encode
  jwt.jwt_encode_callback
  isinstance
  definitions.get
  abort
  Exception
  def_id.definitions.update
  click.command
  inspect.getfile
  location.parsers.add_argument
  definition.pop
  retrieved_schema.viewitems
  package_spec.origin.replace
  os.environ.get
  path_def.values
  paths.values
  APIDocsView.as_view
  parser.parse_args
  EmptyView.as_view
  apispec_swag.get
  swagger.app.app_context
  data.get
  filename.endswith
  PetSchema
  jsonschema.FormatChecker
  get_schema_specs
  set_from_filepath
  swag.init_app
  self.load_config
  os.getcwd
  definitions.update
  UserAPI.as_view
  stream.read
  node.extend
  cat.get
  swag_path.replace
  doc.get.get
  UserPostView.as_view
  spec.to_flasgger
  example_blueprint.add_url_rule
  function.__annotations__.items
  flasgger.utils.validate
  srule.startswith
  final_filepath.split
  key.srule.paths.update
  definitions.items
  authenticate
  grep
  PostAPIView.as_view
  is_valid_method_view
  self.init_app
  os.sep.swag_path.replace.replace
  full_doc.rfind
  swag.update
  str
  source.get
  swagger.config.get
  self.validation_error_handler
  received.items
  wrap_view
  ordered_dict_to_dict
  f.read
  FlaskPlugin
  ItemMethodView.as_view
  remove_suffix
  self.CachedLazyString.super.__init__
  OAuthRedirect.as_view
  response.data.decode
  import_prop.start
  callbacks.values
  jwt_required
  fields.String
  source.items
  username_table.get
  name.definitions.update
  specs.update
  raw.startswith
  app.config.get
  mod.__name__.split
  new_d.items
  target.setdefault
  os.path.abspath
  find_packages
  location.parsers.parse_args
  BPUserPostView.as_view
  swag.get_schema
  jwt.request_handler
  parts.lower
  JWTError
  dict
  f
  import_prop.group
  examples_dir.replace
  self.APISpecsView.super.__init__
  self.text_type
  self.register_views
  super
  app.add_url_rule
  utils.extract_schema
  specs_data.items
  Length
  rule.rule.startswith
  raw_definitions.get
  MarshmallowPlugin
  argparse.ArgumentParser
  Animals.as_view
  sub.index
  self.add_headers
  desc
  inspect.getdoc
  open
  process_doc
  d.items
  abort_if_todo_doesnt_exist
  fields.Str
  specs.append
  value.startswith
  parsers.keys
  sorted
  doc.get.get.items
  received.get
  request_body.get
  check_auth
  param.get
  param.get.get
  full_doc.find
  self.config.get
  Flask
  type
  getattr
  auth_header_prefix.lower
  re.findall
  file_content.rfind
  validation_function
  self.load_swagger_file
  json.dump
  ItemsView.as_view
  spec.get
  cat.items
  self.data.dump
  request.url_rule.str.split
  defi.lower
  request.json.get
  validation_error_handler
  item.get
  swag_annotation
  method.__dict__.get
  schema2jsonschema
  format
  render_template
  d.get.get
  actual_schema.items
  is_openapi3
  rule_filter
  hasattr
  Blueprint
  pathify
  jsonschema.validate
  data
  self.vars.items
  click.option
  fname.fpath.open.read
  RuntimeError
  apispec.get
  redirect
  schema.__name__.replace
  swag.extract_schema.get
  example_blueprint.route
  swag.validate
  KeyError
  parse_definition_docstring
  is_path
  d_schema_id.lower
  iter
  click.echo
  os.path.splitext
  issubclass
  kwargs.pop
  schema_id.lower
  received.viewitems
  PaletteView.as_view
  partial
  os.sep.join
  client.put
  self.loader
  openapi.OpenAPIConverter
  callbacks.items
  validate
  self.DEFAULT_CONFIG.copy
  schema_id.split
  setattr
  verbs.append
  auth_header_value.split
  swag.setdefault
  self.validation_function
  inspect.isclass
  json.loads
  DispatcherMiddleware
  self.LazyJSONEncoder.super.default
  len
  app.register_blueprint
  os.path.join
  subitem.dump
  annotation.to_specs_dict
  get_examples
  url_for
  base_path.endswith
  defaultdict
  AttributeError
  rule.endpoint.startswith
  User
  request.form.get
  spec.path
  APISpec
  model_filter
  subprocess.check_call
  max
  fpath.endswith
  spec.components.schema
  vars
  __replace_ref
  responses.values
  Meow.as_view
  self.last_event.dump
  retrieved_schema.items
  client.get
  responses.items
  DEFAULT_FIELDS.items
  self.config.update
  TODOS.keys
  api.add_resource
  swag_from
  swag.get.get
  parser.add_argument
  filepath.startswith
  d.get
  subs.append
  fields.Nested
  self.is_openapi3
  OrderedDict
  properties.values
  schema.get
  self.parse_request
  client.post
  extract_schema
  imported_doc.replace
  click.File
  examples.items
  blueprint.add_url_rule
  request.method.lower
  request.endpoint.lower.replace
  self.update_schemas_parsers
  item.update
  hack
  request.headers.get
  srule.replace
  decorator
  import_module
  alernative_schema.update
  annotation
  codecs.open
  self.get_url_mappings
  validate_annotation
  filename.startswith
  spec.get.self.get_def_models.items
  self.get_def_models
  defi.copy
  fields.Int
  parse_imports
  callable
  sys.path.append
  data.str.lower
  TODOS.keys.max.lstrip
  openapi_version.str.split
  join
  self.definition_models.append
  verb_swag.get
  userid_table.get
  JWT
  markdown
  SwaggerDefinition
  endpoint.__dict__.get
  full_doc.startswith
  load_from_file
  Markup
  set
  yaml_file.read
  extract_definitions
  variable.annotation.validate_annotation
  data.setdefault
  any
  self.set_schemas
  has_valid_dispatch_view_docs
  an.to_specs_dict
  request.args.get
  endpoint.replace
  detect_by_bom
  inspect.stack
  swag.get
  importlib.util.find_spec
  LazyString
  safe_str_cmp
  set_from_specs_dict
  all_colors.get
  function
  contents.strip
  data.update
  full_doc.replace.strip
  time.time
  current_app.swag.get_apispecs
  os.path.isfile
  list
  os.path.dirname
  _extract_array_defs
  app.route
  APIDocsView
  fields.List
  request.form.keys
  tuple
  loader
  paths.get
  OAuthRedirect
  get_path_from_doc
  func
  json.dumps
  self.SwaggerView.super.dispatch_request
  fpath
  setup
  specs_data.values
  cat.viewitems
  current_app.url_map.iter_rules
  yaml.safe_load
  actual_schema.viewitems
  text.replace
  jsonify
  get_root_path
  os.path.expanduser
  parse_docstring
  regex.sub
  Path
  get_vendor_extension_fields
  self.APIDocsView.super.__init__
  int
  print
  TestView.as_view
  run_simple
  spec.to_dict
  schema2parameters
  SubItem
  doc.get
  value.get
  swag_path.split
  resp.headers.extend
  methods.items
  defs.append
  view_args.get
  convert_schemas
  merge_specs
  swag.definition
  password.encode
  flasgger.utils.apispec_to_template
  PetSchema.dump
  app.app_context
  new_v.append
  file.read
  os.listdir
  self._func
  copy.deepcopy
  </pre>
  </details>
  
      
  
  @vshih 
  Could please help me check this issue?
  May I pull a request to fix it?
  Thank you very much.
  