#40 Publish to PyPi using GitHub Actions

[adiroiban]

Fixes #40

It was the ci.yaml vs ci.yml but also the write permission for the token was missing.

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A push to testing looks ok ... it fails as the version was not ok, as it was not generated for a tag.

https://github.com/twisted/constantly/actions/runs/6690686556/job/18176460120?pr=41#step:8:20

I don't know how to override versioneer: https://github.com/python-versioneer/python-versioneer/issues/199

[adiroiban]

First commit is just for testing, to see if the API works