Cut a beta release with #3569 in it

[peterebden]

Arguably this could be a patch version since there isn't supposed to be anything user-visible, but I feel a bit weird cutting betas of a patch. Can be persuaded either way though.

[chrisnovakovic]

I think the release action might fail because it won't find a section heading with the corresponding version number in the ChangeLog - I might be wrong though, I haven't looked at that code in a while.

[peterebden]

I think the release action might fail because it won't find a section heading with the corresponding version number in the ChangeLog - I might be wrong though, I haven't looked at that code in a while.

We don't have anything in the changelog with a beta heading, and we've definitely done them before, so I think this must work somehow.
I guess if it doesn't I can figure something out. Ideally I think it should check the non-beta version, but it's possible it just doesn't generate release notes for betas.