fix: create target branch without switching workspace in promote-branch workflow

Agent-Logs-Url: https://github.com/petesramek/polyline-algorithm-csharp/sessions/8a7d8752-2079-4fae-a8c8-13b46a0a4629

Co-authored-by: petesramek <2333452+petesramek@users.noreply.github.com>

Author: Copilot

.github/workflows/promote-branch.yml

@@ -206,13 +206,12 @@ jobs:
           dotnet-version: ${{ env.dotnet-sdk-version }}
       - name: 'Create target branch'
         if: ${{ needs.workflow-variables.outputs.target-branch-exists == 'false' }}
+        env:
+          base-branch: ${{ needs.workflow-variables.outputs.base-branch }}
+          target-branch: ${{ needs.workflow-variables.outputs.target-branch }}
         run: |
-          git config user.name "$(git log -n 1 --pretty=format:%an)"
-          git config user.email "$(git log -n 1 --pretty=format:%ae)"
           git fetch origin
-          git switch ${{ needs.workflow-variables.outputs.base-branch }}
-          git checkout -b ${{ needs.workflow-variables.outputs.target-branch }} origin/${{ needs.workflow-variables.outputs.target-branch }} || git checkout -b ${{ needs.workflow-variables.outputs.target-branch }}
-          git push --set-upstream origin ${{ needs.workflow-variables.outputs.target-branch }}
+          git push origin origin/${{ env.base-branch }}:refs/heads/${{ env.target-branch }}
       - name: 'Lock target branch'
         if: ${{ needs.workflow-variables.outputs.target-branch-exists == 'false' }}
         uses: './.github/actions/github/branch-protection/lock'