! pyyaml 5.4.1 workaround

.github/workflows/commit.yml

@@ -55,8 +55,12 @@ jobs:
         with:
           python-version: ${{ matrix.python-version }}
 
+        # PyYaml 5.4.1 requires cython < 3.0.0 for Python 2.7
       - name: Install dependencies
-        run: python -m pip install --no-deps -r requirements.txt
+        run: |
+          python -m pip pip install "cython<3.0.0"
+          python -m pip install --no-build-isolation pyyaml==5.4.1
+          python -m pip install --no-deps -r requirements.txt
 
       - name: Create .env
         run: |