Change git branch check from source to target

[jorris]

As Konflux RPM builds have evolved, it is apparent that we want the check to be against target branches, not source. Source branches are arbitrarily named

JIRA: ROK-923

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

Files with missing lines	Coverage Δ
policy/release/git_branch/git_branch.rego	100.00% <100.00%> (ø)
policy/release/git_branch/git_branch_test.rego	100.00% <100.00%> (ø)

... and 2 files with indirect coverage changes

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[simonbaird]

I checked an attestation and I see that we get the branch in different formats.

Example:

• "build.appstudio.redhat.com/target_branch": "main"
• "pipelinesascode.tekton.dev/source-branch": "refs/heads/main"

Will the matching still work if you just get branch name "main" instead of the full git ref?

[simonbaird]

Lgtm. Are you happy to merge, or do you want to wait for the data change PR to merge first?

[jorris]

Lgtm. Are you happy to merge, or do you want to wait for the data change PR to merge first?

I'm going to add a test for one more branch pattern to add to the release data. If that passes, I'll merge the release data first then this one.