title: GitHub actions to trigger build on new Pull Requests
body: <p>I have the following workflow to trigger CMake builds on my GitHub project:</p>
  <pre><code>name: C/C++ CI
  
  on:
    push:
      branches: [ master, develop ]
    pull_request:
      types: [ opened, edited, reopened, review_requested ]
      branches: [ master, develop ]
  
  jobs:
    build:
  
      runs-on: ubuntu-18.04
  
      steps:
      - name: Install deps
        run: sudo apt-get update; sudo apt-get install python3-distutils libfastjson-dev libcurl4-gnutls-dev libssl-dev -y
      - uses: actions/checkout@v2
      - name: Run CMake
        run: mkdir build; cd build; cmake .. -DCMAKE_INSTALL_PREFIX=/home/runner/work/access/build/ext_install;
      - name: Run make
        run: cd build; make -j8
  </code></pre>
  <p>I expected it to trigger builds on new Pull Requests and have the build status as a condition to approve the merging.</p>
  <p>However I'm finding it a bit challenging to achieve such results. I'm sort of a newbie when it comes to GitHub Actions.</p>