No bug: Fetch correct reference for target branch in CI

Merge Info

Merging

Target Branches

• tor-browser - !fixups to tor-browser-specific commits, new features, security backports
• base-browser and mullvad-browser - !fixups to base-browser-specific commits, new features to be shared with mullvad-browser, and security backports
  • ⚠️ IMPORTANT: Please list the base-browser-specific commits which need to be cherry-picked to the base-browser and mullvad-browser branches here

Target Channels

• Alpha: esr128-14.5
• Stable: esr128-14.0
• Legacy: esr115-13.5

Backporting

Timeline

• No Backport (preferred): patchset for the next major stable
• Immediate: patchset needed as soon as possible (fixes CVEs, 0-days, etc)
• Next Minor Stable Release: patchset that needs to be verified in nightly before backport
• Eventually: patchset that needs to be verified in alpha before backport

Review

Change Description

Branches in the local repository copy may have a prefix if they are not the default branch. The lack of that prefix has been failing our pipelines that do not point to a default branch or a branch that has not been the default before. This MR attempts to fix that with some bash (and pwsh) magic.

How Tested

I created this on purpose pointing to base-browser branch. If the CI passses here, we should be fine.