Add black before commit checks

Author: CoMPaTech

.github/workflows/verify.yml

@@ -77,6 +77,8 @@ jobs:
       uses: actions/setup-python@v2
       with:
         python-version: ${{ env.DEFAULT_PYTHON }}
+    - name: Pre-black
+      uses: psf/black@stable
     - name: Restore base Python ${{ env.DEFAULT_PYTHON }} virtual environment
       id: cache-venv
       uses: actions/cache@v2