tooling: add black and flake8 for python formatting/linting (#6454)

.github/workflows/ci.yml

@@ -9,6 +9,10 @@ jobs:
     name: CI
 
     steps:
+    - name: Setup Python
+      uses: actions/setup-python@v2
+      with:
+        python-version: 3.8
 
     - name: Checkout
       uses: actions/checkout@v2
@@ -22,6 +26,9 @@ jobs:
     - name: Install npm dependencies
       run: npm ci
 
+    - name: Install python dependencies
+      run: python3 -m pip install -r requirements.txt
+
     - name: Test
       run: npm test