Added pypy-dev to CI as an requirement

.github/workflows/ci.yml

@@ -22,6 +22,7 @@ jobs:
                   python-version: ${{ matrix.python-version }}
             - name: Install dependencies
               run: |
+                  sudo apt -y install pypy-dev
                   sudo apt -y install libzbar0
                   pip install -r tests/requirements.txt
                   pip install flake8