ci: change backport config (#273)

(cherry picked from commit 76fc626)

.github/workflows/backport.yml

@@ -1,24 +1,26 @@
-name: Automatic backport action
-
+name: Backport
 on:
   pull_request_target:
-    types: ["labeled", "closed"]
+    types:
+      - closed
+      - labeled
 
 jobs:
   backport:
-    name: Backport PR
+    name: Backport
     runs-on: ubuntu-latest
+    # Only react to merged PRs for security reasons.
+    # See https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#pull_request_target.
+    if: >
+      github.event.pull_request.merged
+      && (
+        github.event.action == 'closed'
+        || (
+          github.event.action == 'labeled'
+          && contains(github.event.label.name, 'backport')
+        )
+      )
     steps:
-      - name: Backport Action
-        uses: sorenlouv/[email protected]
+      - uses: tibdex/backport@v2
         with:
-          github_token: ${{ secrets.GITHUB_TOKEN }}
-          auto_backport_label_prefix: backport-to-
-
-      - name: Info log
-        if: ${{ success() }}
-        run: cat ~/.backport/backport.info.log
-
-      - name: Debug log
-        if: ${{ failure() }}
-        run: cat ~/.backport/backport.debug.log
+          github_token: ${{ secrets.GITHUB_TOKEN }}