fixed black command

Author: realDuYuanChao

.github/workflows/code_formatter.yml

@@ -8,7 +8,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v2
-      - uses: psf/black@stable
+      - run: pip install black
       - run: black --check .
       - name: Commit black changes
         if: failure()