add cron schedule for the script

.github/workflows/python-app.yml

@@ -1,6 +1,9 @@
 name: r/developersIndia titles updater
 
 on:
+  schedule:
+    # At 19:30 on every 2nd day-of-week.” 
+    - cron:  '30 19 * * */2'
   workflow_dispatch:
   push:
     branches: [ "main" ]