Feature request: Add label for pull requests that contain package updates

[etu]

We have the label 8.has: package (new) which is added automatically (as long as commits follow the guidelines for commit messages).

I think we should add automatic adding of the label 8.has: package (update) if the commit message follow the form of: ^(.*): (.*) -> (.*)$

This makes it easier to filter pull requests on updates which would make it easier to find potential pull requests that are "easy" to test, for example patch or minor version bumps.