Update documentation workflow to only publish one version per major

[tczekajlo]

Proposed changes:

• Resolves update documentation workflow to only publish one version per major #9711

Status (please check what you already did):

• added some tests for the functionality
• updated the documentation
• updated the changelog (please check changelog for instructions)
• reformat files using black (please check Readme for instructions)

[tczekajlo]

@m-vdb Can you 👀 if you have a minute? I hope I got it right 😄

[m-vdb]

Nice 🎉 thanks a lot @tczekajlo ! I think there is one part missing, about running the docs script itself here, which is creating a new version of the docs for new majors only, not minors. I think we just need to update the two patterns and we should be good to go (at first sight 🤔 )

[m-vdb]

@tczekajlo before merging this PR, I will need to wrap-up this one (remaining step is to merge the 2.8 docs manually into 2.x). I'll put this up today and ask for a review from CSE. Another thing we'll need to do around the same time is disable the docs workflows on at least 2.7, 2.6 (mostly a safety measure, in case people push new tags there. I don't expect it, but....). I can take care of this and I'll ask a review from you if that's alright

[m-vdb]

awesome 💯 @tczekajlo I will approve the PR and merge it once the documentation branch is ready 👍🏻