Added release automation (creates drafts automatically and pushes to pypi on release)

[filipecosta90]

This PR simplifies the release process using github actions. It follows the same approach as redistimeseries-py.

Release drafts

This PR enables automating the release draft process. On every commit to master ( and depending on the tags the PR is classified as feature, bug-fixes or maintenance). We can also ignore PRs from the release if the PR has the skip-changelog label.

Automatic release to PyPi

We need to ensure that the secrets are present prior releasing ( that check action is run on every commit )
secrets required (cc @gkorland):

• TESTPYPI_TOKEN
• PYPI_TOKEN

[jeffreylovitz]

This seems like a great addition to me! Should this PR itself have the skip-changelog label?

I think this is merge-ready as soon as we get confirmation that the appropriate secrets are available.

[filipecosta90]

Should this PR itself have the skip-changelog label?

I was divided between maintenance or skip changelog. changed :)