Fully automate the release process

[daka1510]

What is the expected feature or enhancement?
As a maintainer, I want to release a new version with confidence in a fully automated way.

As-is
Some parts of the release (e.g. push to PyPi) are already automated and triggered when a tag is pushed. Others (e.g. generation of release notes, verification of tests) involve manual steps.

[daka1510]

As a starting point for further discussions, here's a first proposal on how this might work:

1. a maintainer triggers a release-prep workflow and specifies the version as input parameter
2. the release-prep workflow raises a release preparation PR (with a special tag) in the target repository (see [1] for an example)
3. the creation of the release preparation PR triggers a release-qa workflow that runs all necessary quality guards (e.g. unit/integration/lint/code coverage checks). The results of the workflow runs show up as status checks in the PR.
4. a maintainer reviews and integrates the release preparation PR
5. the integration of the release preparation PR triggers a final release workflow that publishes all required release artifacts (e.g. stable branches, tags, docs, PyPi package, updated version files)

This process should mostly align with the described release cycle in the contributing guidelines.

@jyu00, @rathishcholarajan - thoughts?

[jyu00]

I think the process is fairly automated already. Yes someone needs to manually move all the release notes from one directory to another, but a human needs to review all the release notes anyway, so I don't see automating that part buys us much.

In terms of qa, the release PR would already trigger a full run of tests (the push flow, not just pr), except slow tests, which unfortunately we can't wait for because they can run for several hours.

Once a tag is published, uploading to PyPi, generating meta package PR, docs, etc are all automated. We could automated updating the version post release though, since that step is often missed.

[mtreinish]

It's worth noting there are open TODOs on qiskit-bot for these things: Qiskit/qiskit-bot#3 and Qiskit/qiskit-bot#17 I just haven't had time to implement them and nobody else has stepped up

[daka1510]

Thanks for the reference, @mtreinish and details, @jyu00. Good to know the qiskit-bot offers a central place to implement some of the missing pieces that are not yet automated. Will keep this issue open for discussion until we reach a conclusion what we want to automate further (if anything). I personally want to gain some experience with the established release process first and will get back to this topic afterwards.