Add github releases pypi auto upload action

[leifdenby]

Hi @dbstein!

First, thank you for writing fast_interp! I've made a frequent use of it and find it very useful. We're currently using it in a project called advtraj and at the time I included the source-code directly into our tool because it wasn't working with python3 (and I found a small bug, but I think @ReadingClouds has been in touch with you about that). Because we would like to put advtraj on pypi, it would be really great if you would put fast_interp on pypi too.

To help with that this pull-request adds a Github Action which automatically builds and publishes any releases
tagged on github to pypi.org. All you need to do is add 1) add a pypi API key to a "repository secret" for this github repository called PYPI_TOKEN, 2) merge this pull-request and 3) create a release here on github.

Alternatively, if you I could do all this for you if you would trust me to be a collaborator on your repository :)

I use this way of publishing to pypi in many places, you can see an example here: https://github.com/convml/convml-data. It makes it really easy to put new changes on pypi.

You can get a pypi upload token at https://pypi.org/manage/account/token/ and here are instructions on adding this to your repo's secrets: https://docs.github.com/en/actions/security-guides/encrypted-secrets#creating-encrypted-secrets-for-a-repository

[leifdenby]

I just noticed #4, and that you've fixed the bug. Great!

[leifdenby]

@dbstein just a gently nudge to say that if you merge this pull-request then releasing fast_interp on pypi will just be as easy as creating a release on github

[dbstein]

Sorry! Paternity leave took over my life and I forgot. You're probably far more active with this code than I am now, so I've just added you as a collaborator. Seems like the easiest solution.

[curly-t]

Hi @dbstein !

Thanks for this proposal greate thinking! Was searching on pypi and still couldn't find the project. This would be of much help, because it's a greate little package.
Thank you! :)

[leifdenby]

Sorry! Paternity leave took over my life and I forgot. You're probably far more active with this code than I am now, so I've just added you as a collaborator. Seems like the easiest solution.

@dbstein could you add me as co-owner instead? It looks like as a "collaborator" I don't have the "write access" I need to merge this branch :) Thanks!