use PAT token

Signed-off-by: Wei Weng <Wei.Weng@microsoft.com>

Author: Wei Weng

.github/workflows/backport.yml

@@ -24,7 +24,7 @@ jobs:
         with:
           ref: main
           fetch-depth: 0
-          token: ${{ secrets.GITHUB_TOKEN }}
+          token: ${{ secrets.PAT_TOKEN }}
 
       - name: Set up Go
         uses: actions/setup-go@v6
@@ -113,7 +113,7 @@ jobs:
       - name: Create Pull Request
         if: steps.commits.outputs.has_changes == 'true' && steps.merge.outputs.merge_status == 'success'
         env:
-          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GH_TOKEN: ${{ secrets.PAT_TOKEN }}
         run: |
           # Prepare PR body
           cat > /tmp/pr_body.md <<'EOF'