Add utils/tag-release.sh

[troglobit]

To ensure we have references to all submodules we should tag them as well when creating an Infix release.

Could be called from release job.

[mattiaswal]

Seems like git can help us with this:

git submodule foreach git tag -a 1.2.3 -m "test"

will tag all submodules.

[troglobit]

I spent a bit of time today thinking about this. I think this would fit nicely with the release workflow, and it would also be great if we could add support to that to also tag new releases.

Haven't shopped around yet, but I'm betting there's quite a few ready-made actions that fit the bill for us.