Update build_offline_docs.yml

.github/workflows/build_offline_docs.yml

@@ -1,19 +1,14 @@
 name: Build documentation for offline usage
 on:
   workflow_dispatch:
-  schedule:
-    # Every week on Monday at midnight (UTC).
-    # This keeps the generated HTML documentation fresh.
-    - cron: '0 0 * * 1'
 
 jobs:
   build:
     runs-on: ubuntu-22.04
     strategy:
       matrix:
         branch:
-          - master
-          - 3.6
+          - 4.2
     steps:
       - uses: actions/checkout@v4
         with: