Update CI & add black formatter

.github/workflows/test.yml

@@ -38,14 +38,12 @@ jobs:
     - name: Install test dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install flake8 pytest
+        pip install black pytest
 
-    - name: Lint with flake8
+    - name: Lint with Black
       run: |
-        # stop the build if there are Python syntax errors or undefined names
-        flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
-        # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
-        flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+        cd ..
+        python -m black qlib -l 120
 
     - name: Unit tests with Pytest
       run: |