Fix workflow to run on ubuntu-latest

Author: memurats

.github/workflows/update-stable-titles.yml

@@ -14,7 +14,8 @@ concurrency:
 
 jobs:
   update-pr-title:
-    runs-on: ubuntu-latest-low
+    if: github.repository == 'nextcloud/server'
+    runs-on: ubuntu-latest
     permissions:
       pull-requests: write
       contents: read