title: Run GitHub Actions on all open PR branch when commits are pushed to base branch
body: <p>I am using GitHub Actions to run certain tasks on the PR branches like version bumping for the application. As part of this, I wanted to trigger the actions to run on all open PRs when a commit is made to the base branch, say <code>main</code>. The config I have in my workflow is</p>
  <pre><code>on:
    push:
      branches: ['main']
    pull_request:
      branches: ['main']
      types: [opened, reopened, synchronize]
  </code></pre>
  <p>This triggers when there is a <code>push</code> event on the <code>main</code> branch but the action runs on the <code>main</code> branch itself. I don't want to bump my versions directly on the main branch. The version bump must be done in the PR before it is merged to the <code>main</code> branch. The reason behind this is my CI/CD pipeline listens to the <code>main</code> branch for changes. If I do a version bump after my PR merge, it will trigger twice.</p>
  <p>I had to used <code>if: &quot;(github.event_name == 'pull_request')&quot;</code> on my job to skip the action on the <code>main</code> branch.</p>
  <p><strong>Question:</strong> How do I trigger the GitHub Actions on all open PRs when there is a change pushed to the base branch?</p>