Run backports on Merging onstead of PR synchronization

.github/workflows/backport.yml

@@ -3,8 +3,13 @@ name: Backport
 #   pull_request_target:
 #     types: [opened, closed, labeled, unlabeled, synchronize]
 on:
-  pull_request_target:
-    types: [opened, closed, labeled, unlabeled, synchronize]
+  push:
+    branches:
+      - 'master'
+      - '[0-9].[0-9]+'  # matches to backport branches, e.g. 3.6
+    tags: [ 'v*' ]
+  # pull_request_target:
+  #   types: [opened, closed, labeled, unlabeled, synchronize]
 
 jobs:
   backport:
@@ -13,11 +18,11 @@ jobs:
     # not awailable for forks, skip the workflow
     # if: ${{ github.event.pull_request.head.repo.full_name == 'aio-libs/aiohttp' }}
     steps:
-      # - id: generate_token
-      #   uses: tibdex/github-app-token@v1
-      #   with:
-      #     app_id: ${{ secrets.BOT_APP_ID }}
-      #     private_key: ${{ secrets.BOT_PRIVATE_KEY }}
+      - id: generate_token
+        uses: tibdex/github-app-token@v1
+        with:
+          app_id: ${{ secrets.BOT_APP_ID }}
+          private_key: ${{ secrets.BOT_PRIVATE_KEY }}
       - name: Backport
         uses: sqren/backport-github-action@v1
         with:
@@ -43,7 +48,7 @@ jobs:
 
           # Optional
           # If no labels match the `backport_label_pattern` the backport check will fail. To bypass this for a single PR you can add a label to indicate the PR should not be backported
-          # skip_backport_check_label: 'backport:skip'
+          skip_backport_check_label: 'backport:skip'
 
           # Optional
           # If no labels match the `backport_label_pattern` the backport check will fail. Enabling this will bypass the check for all PRs