Update tests.yml

Former-commit-id: 34151675388701afa40220729a63b0d7b2fa2a7c

.github/workflows/tests.yml

@@ -14,6 +14,16 @@ jobs:
     steps:
       - uses: actions/checkout@v3
 
+      - name: Set up Python
+        uses: actions/setup-python@v3
+        with:
+          python-version: "3.8"
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install black ruff
+
       - name: Check quality
         run: |
             make style && make quality