Remove push trigger from workflow

The push trigger was added so that the workflow would show up
on the Actions tab on GitHub.

Author: kiran-garre

.github/workflows/docs-generator.yaml

@@ -7,7 +7,6 @@ on:
         description: 'Number of PR to document'
         required: true
         type: string
-  push:
 
 jobs:
   generate_docs: