I'd like to create a pre-receive script that would be started on GitHub server when an engineer clicks on 'Create pull request'. The script would then check the description of the pull request for a specific content and if that content is not part of the description the pull request would be rejected. I've created pull_request_template.md file that should be filled prior to creating the pull request. Shortly, I'd like the pull request to be rejected if the information requested in description template are not provided.
My question is: how to check and/or parse the content of pull request's description?