ci: fix to make pr label job required check (#756)

* ci: fix to make pr label job required check

Signed-off-by: Paul S. Schweigert <paul@paulschweigert.com>

* don't run label job in merge queue

Signed-off-by: Paul S. Schweigert <paul@paulschweigert.com>

* multi-step

Signed-off-by: Paul S. Schweigert <paul@paulschweigert.com>

---------

Signed-off-by: Paul S. Schweigert <paul@paulschweigert.com>

Author: psschwei

.github/workflows/pr-label.yml

@@ -3,6 +3,7 @@ name: "Label PR by conventional commit prefix"
 on:
   pull_request_target:
     types: [opened, edited, synchronize]
+  merge_group:
 
 jobs:
   label:
@@ -12,6 +13,7 @@ jobs:
       issues: write
     steps:
       - name: Apply label based on PR title prefix
+        if: github.event_name == 'pull_request_target'
         uses: actions/github-script@v7
         with:
           script: |
@@ -45,3 +47,8 @@ jobs:
               issue_number: context.payload.pull_request.number,
               labels: [label],
             });
+      - name: Skip label in merge queue
+        if: github.event_name == 'merge_group'
+        run: echo "PR title already validated at PR open/edit time"
+
+