Add release workflow file to publish to PyPI

[nicovank]

Hey!

Thanks for making this tool :) It would be nice to be able to install it directly from PyPI. bibcheck is taken, but bibchecker is available.

This PR consists of a GH action that will automatically publish to GitHub every time you do a new release from here. One important thing is to always bump the version in pyproject.toml before issuing a new release, or the action will fail (in which case, deleting release and tag, bumping version, and re-doing release is the easiest fix).

If you're interested in setting this up:

1. Make an PyPI account if you don't have one
2. Go to the publishing page: https://pypi.org/manage/account/publishing/, and in the pending publisher form enter:
   1. PyPI Project Name: BibChecker
   2. Owner: bienz2
   3. Repository name: BibChecker
   4. Workflow name: release.yml
   5. Environment name: leave blank
3. Merge this PR.
4. Make a new/initial release here (I like to tag it with the version number e.g. v1.0.1. Title and body are optional).

Noting that I wasn't able to fully test this, so hopefully it works on the first run :) (but I've written similar actions in other repos).

If you prefer users to always clone and use from head then just close this PR. Thanks!

[bienz2]

Absolutely, this is a great idea! I am actually in the middle of password recovery with PyPI as I lost access to the email I originally signed up with. As soon as the recovery is finished, I will definitely add it!