ci: update release-please workflow (2)

Author: Mattia Roccoberton

Diff for: .github/workflows/release-please.yml

@@ -1,5 +1,8 @@
 ---
 on:
+  pull_request:
+    types: [labeled]
+
   push:
     branches:
       - main
@@ -14,7 +17,7 @@ jobs:
   release-please:
     runs-on: ubuntu-latest
     steps:
-      - uses: google-github-actions/release-please-action@v4
+      - uses: google-github-actions/release-please-action@v3
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
           release-type: ruby