Add no no-deps flags

Ref: jazzband/pip-tools#1752

.github/workflows/testing.yml

@@ -30,7 +30,7 @@ jobs:
         run: python -m pip install --upgrade pip
 
       - name: Install dependencies
-        run: pip install -r test-requirements.txt
+        run: pip install --no-deps -r test-requirements.txt
 
       - name: Lint with flake8
         run: pre-commit run --all-files flake8