PR Labels

[mmclane]

Checklist

• I've searched the issue queue to verify this is not a duplicate feature request.
• I've pasted the output of kargo version, if applicable.
• I've pasted logs, if applicable.

kargo v1.0.3

Proposed Feature

It would be really great if we could set PR labels via the git-open-pr step.

Motivation

We like to use them to filter our PRs in github and it would be nice if we didn't have to do this after the PR is created.
Additionally, one could have a github action triggered based on the label being added and the value. While I don't have an immediate use case for this, I could see how I might use it.

Suggested Implementation

The git-open-pr promotion step could have a configuration item that is Labels that is of type list of strings. Each item in the list is added as a label after the PR is opened.

It would be worth noting that the labels have to pre-exist in your github repo for the workflow to add the label, but that would be on the creator of the workflow to insure.

[mmclane]

I suspect there are a number of things that could be done here and you guys just haven't gotten to it yet. For instance, it would be nice to be able to specify what the PR title is to override using the last commit message.