Fix documentation generation

[Conengmo]

I noticed our documentation hasn't been updated since we moved away from Travis. Probably something wrong in our Github Actions workflow. I noticed we don't run the workflow on release, could that be the issue? To possibly solve this I copied the triggers from the 'Publish to PyPI' workflow.

If this would indeed solve the issue, I suspect we would then have to do a release to update the documentation. Or should I just run the documentation and update the gh-pages branch manually?

[martinfleis]

These will not do much apart from checking if sphinx did not fail as the last step will run only on release. But the lines below are needed here.

[martinfleis]

If this would indeed solve the issue, I suspect we would then have to do a release to update the documentation. Or should I just run the documentation and update the gh-pages branch manually?

I would run it manually and push to the branch.

[Conengmo]

Thanks for the review Martin. I'll run the docs manually and add a PR to add them to the gh-pages branch. Then also merge this so we have the 'on release' trigger for our next release.

These will not do much apart from checking if sphinx did not fail as the last step will run only on release

Agreed, but I suppose it's nice to check that on each PR.