Give possibility to deploy/redeploy the same versions

[akolacz]

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.

Proposed Feature

We want to give the possibility to deploy/redeploy the same version through Kargo

Motivation

When we have our deployment/promotion through Kargo. For example the deployment was stuck/error on an pod/job and we fixed it directly on ArgoCD to successfully deployed the new versions. On Kargo the status of the promotion is in error we can't today redeploy the same versions through Kargo because we have the following error (that makes sense).

failed to run step "git-open-pr": error creating pull request: POST https://api.github.com/repos/my-company/my-repo/pulls: 422 Validation Failed [{Resource:PullRequest Field: Code:custom Message:No commits between main and kargo/my-repo/dev/promotion}]

with the following promotion steps:

But I know before the promotions steps was added, previously we can redeploy the same versions just to say to Kargo to update the status of the promotion to green/succeeded.
Because right now the only way to put back to succeeded on Kargo is to rollback on the previous versions and redeploy the latest one, or modify manually the versions updated by kargo into our repository to say to Kargo, it's not the same versions between what you want to push and in the code.

[jessesuen]

I'm guessing this is mainly a problem for the git-open-pr step?

[krancour]

This possibly ties into #3228

[hiddeco]

Think that in addition to #3228, you would probably find yourself wanting to introduce conditional steps as well (#3125).

I.e.

steps:
- uses: git-open-pr
  as: open-pr
  config:
    ignoreIdenticalBranches: true
- uses: git-wait-for-pr
  if: ${{ outputs['open-pr'].prNumber != 0 }} # Would cause the step to be skipped if no PR number is assigned