tests need all the prereqs, too

.github/workflows/pylint.yml

@@ -18,7 +18,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install pylint mysqlclient
+        pip install pylint mysqlclient black
     - name: Check for compile errors with pylint
       run: |
         pylint -E $(git ls-files '*.py')