[DOC] Add PyPI description

[hectormz]

PR Description

Please describe the changes proposed in the pull request:

• Copy relevant sections from README.rst for PyPI project description

This PR resolves #495.

PR Checklist

Please ensure that you have done the following:

1. PR in from a fork off your branch. Do not PR from <your_username>:master, but rather from <your_username>:<branch_name>.

2. If you're not on the contributors list, add yourself to AUTHORS.rst.

3. Add a line to CHANGELOG.rst under the latest version header (i.e. the one that is "on deck") describing the contribution.
   • Do use some discretion here; if there are multiple PRs that are related, keep them in a single line.

Quick Check

To do a very quick check that everything is correct, follow these steps below:

• Run the command make check from pyjanitor's top-level directory. This will automatically run:
  • black formatting
  • pycodestyle checking
  • running the test suite
  • docs build

Once done, please check off the check-box above.

If make check does not work for you, you can execute the commands listed in the Makefile individually.

Documentation Changes

If you are adding documentation changes, please ensure the following:

• Build the docs locally.
• View the docs to check that it renders correctly.

Relevant Reviewers

Please tag maintainers to review.

• @ericmjl

[ericmjl]

Thanks for taking care of this, @hectormz! Just a question regarding whether we can reduce duplication in the code, mostly for maintenance purposes.

[codecov]

Codecov Report

Merging #513 into dev will decrease coverage by 0.11%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##              dev     #513      +/-   ##
==========================================
- Coverage   92.88%   92.77%   -0.12%     
==========================================
  Files          10       10              
  Lines         872      872              
==========================================
- Hits          810      809       -1     
- Misses         62       63       +1

[hectormz]

@ericmjl Seems there is an issue finding the conda environment.

In this change, I considering making a test, but was unsure how to test something in setup.py, so I added the assert.

[ericmjl]

@hectormz, it's only failing on black at this point, I think! 😄 Could you black the entire codebase and push?

[hectormz]

Hi @ericmjl, black and pycodestyle were in disagreement about a line in setup.py. Maybe this fix will do the job

[ericmjl]

All good! Thanks @hectormz!