Add release job on tag

[LiadOz]

This workflow will create a distribution and upload it to pypi when a tag is pushed, this does not require setting up API keys in the repository, see more here
In order for this to work the project needs to be registered here https://pypi.org/manage/account/publishing/ with the following parameters:

@vmalloc Before merging this, can you try tagging this commit with a prerelease version to see that it indeed works, I have only tested it with TestPyPI

[vmalloc]

@LiadOz many thanks for your work on this! I just tested it releasing 1.6.0a1 and it seems to have succeeded!

One question though - isn't the pipeline as it is currently configured going to allow publishing versions that actually fail CI? To my understanding the two chores run in parallel and are not inter-dependent...

[LiadOz]

@vmalloc I took a look at some of the most prominent python packages to see how they handle version releases with Github actions. I found that there are two approaches, both of these approaches do not test the code before publishing to pypi (they likely rely on the fact that the main branch has already passed the testing pipelines)
Approach 1 - Use publish event, for example https://github.com/python-poetry/poetry/blob/main/.github/workflows/release.yaml
Approach 2 - Use push event and make sure the test pipeline does not trigger on tags https://github.com/python/mypy/blob/master/.github/workflows/build_wheels.yml
I prefer the second approach because it doesn't require you to use the GUI to make a release. Let me know if you want me to use the first approach instead.

[vmalloc]

All I am concerned about is that currently the publish stage is run in parallel to the build/test phase, which could lead to a release being pushed that retroactively turns out to have failed testing

[LiadOz]

ok, then approach 1 should fit more here, since the other option will not run the test pipeline

[LiadOz]

@vmalloc Now after putting a tag and verifying that the pipeline is ok, you can make a release out of that tag which will publish the package to pypi.

[oren0e]

@vmalloc Hi! Do you have an eta when this can be ready? I assume it holds back #20

[vmalloc]

Sorry for the delay - @LiadOz awesome work - thanks!

I will merge this and cut out the 1.6.0 release now