Update release job condition

Author: sitiom

.github/workflows/nightly.yml

@@ -59,7 +59,7 @@ jobs:
 
   release:
     needs: [checkver, build]
-    if: ${{ github.event_name == 'push' || github.event_name == 'schedule' }}
+    if: ${{ github.event_name != 'pull_request' }}
     runs-on: ubuntu-latest
     permissions:
       contents: write