Given following log snippets, their explanation, and nothing else, explain what failure, if any, occurred during build of this package.

  Snippets are in a format of [X] : [Y], where [X] is a log snippet, and [Y] is the explanation.

  Snippets are delimited with '================'.

  Drawing on information from all snippets, provide a concise explanation of the issue and recommend a solution.

  Explanation of the issue, and recommended solution, should take a handful of sentences.

  Snippets:

  [ValueError: invalid pyproject.toml config: `project.license`.
configuration error: `project.license` must be valid exactly by one definition (2 matches found):
    - keys:
        'file': {type: string}
      required: ['file']
    - keys:
        'text': {type: string}
      required: ['text']]: [This error specifies that pyproject.toml content is invalid, in particular the "project.license" field.]

Issue: The file structure of pyproject.toml wasn't valid in the current environment, in particular the "project.license" field. That field needs to be a table with a "file" or a "text" key.
Please note that the specified project.license format was deprecated in favor of a simple text-only field in newer Python version. That means you might be trying to build a project expecting newer Python versions in an environment with older Python version.
Resolution: Adjust the pyproject.toml file and its included "project.license" field to match the specification. Alternatively, if you want to use a text-only definition of the field, use a newer Python version to build it.