Fix: Use latest python version for black

.github/workflows/testing.yml

@@ -71,10 +71,10 @@ jobs:
     steps:
     - name: Checkout
       uses: actions/checkout@v4
-    - name: Set up Python 3.7
+    - name: Set up Python 3.x
       uses: actions/setup-python@v5
       with:
-        python-version: 3.7
+        python-version: 3.x
     - name: Black
       run: |
         python -m pip install --upgrade pip