text: Title: Huge Requirements.txt for pyjanitor 
  Body: Hi ,
  
  I am using some basic functions from pyjanitor such as - clean_names() , collapse_levels() in one of my code which I want to productionise.
  And there are limitations on the size of the production code base.
  Currently ,if I just look at the requirements.txt for just "pyjanitor" , its huge .
  I don't think I require all the dependencies in my code.
  How can I remove the unnecessary ones ?
  Or Whats the best approach to productionize the code which uses the above basic pyjanitor functions. 
  
  To get requirement.txt file,  I did  --
  python -m venv test_env
  pip install pyjanitor
  pip freeze > pyjanitor_req.txt
  
  [pyjanitor_req.txt](https://github.com/ericmjl/pyjanitor/files/5878504/pyjanitor_req.txt)
  