title: Create Pull Request on Git Push
body: <p>I have GitHub repository with 2 branches: "master" &amp; "develop".</p>
  
  <p>The workflow for us is that any code should be committed to the "develop" branch then pushed to GitHub, then a Pull Request should be created to merge the commits into the "master" branch.</p>
  
  <p>I am trying to write an Action that will create a Pull Request once a developer pushes commits to the branch "develop" and had the following script:</p>
  
  <pre><code>name: Create pull request
  on:
    push:
      branches:
        - develop
  jobs:
    prForMasterBranch:
      runs-on: ubuntu-latest
      steps:
        - uses: actions/checkout@v2
          with:
            ref: master
        - name: Create Pull Request
          uses: peter-evans/create-pull-request@v2
          with:
            commit-message: update master branch
            title: Update master branch
            branch: develop
  </code></pre>
  
  <p>I can see that this action has executed successfully on "Push" event of the "develop" branch, but I can't see any new Pull Requests!</p>
  
  <p>I checked the logs for the action and found these lines at the end of pull request creation:</p>
  
  <blockquote>
    <p>Pushing pull request branch to 'origin/develop'<br>
    Branch 'develop' no longer differs from base branch 'master'<br>
    Closing pull request and deleting branch 'develop'</p>
  </blockquote>
  
  <p>It seems I am missing something, but couldn't figure it out.</p>
  
  <p>Any help is appreciated.</p>