Check commit signatures

[jctanner]

Description 🛠

Signatures are required on all commits, but we're not enforcing it via any known mechanism other than hoping it's caught by human review.

Reviewer Checklists 👀

Developer reviewer:

• Code looks sound, good architectural decisions, no code smells
• There is a Jira issue associated (note that "No-Issue" should be rarely used)
• Tests are included in galaxy_ng/tests/integration or galaxy_ng/tests/functional, and they fully cover necessary test scenarios… or tests not needed

QE reviewer (exceptions):

• Tests are included in galaxy_ng/tests/integration or galaxy_ng/tests/functional, and they fully cover necessary test scenarios… or tests not needed
• PR meets applicable Acceptance Criteria for associated Jira issue

Note: when merging, include the Jira issue link in the squashed commit

[mdellweg]

You know you can configure that in GH branch protection rules?

[rochacbruno]

@mdellweg it is already checked but that config prevents merges to the specific branch eg: master the developer will not be notified about it, it will only prevent the merge, and it would be useful to have this check to notify the developer during PR check.