title: Customizing slack notification for Github pull requests
body: <p>I have a use case wherein every time a pull request is raised against the develop branch, a notification needs to be sent to slack channel with PR link and possibly info on which user opened it.</p>
  <p>I'm confused as to which path to take</p>
  <ol>
  <li>Github actions which posts to slack</li>
  <li>Github app for slack(<a href="https://github.com/integrations/slack#configuration" rel="noreferrer">https://github.com/integrations/slack#configuration</a>)</li>
  </ol>
  <p>After going through <a href="https://github.com/integrations/slack#configuration" rel="noreferrer">https://github.com/integrations/slack#configuration</a>, I see the option to subscribe solely to pull requests with <code>/github subscribe org/repo pulls</code>, but this does not allow customizations(e.g. only notify for PRs to develop, not for every PR)</p>
  <p>Github actions has ways to specify to only run when pull request is raised for develop, but since it is repository specific, I'll have to push the workflow file to 100+ repositories</p>
  <p>Is there a better solution/automation to post to slack when a PR is raised(not merged) to a specific branch and customizable(like adding user info who opened the PR)?</p>