dependency: update Ballad to 2.0.0a2 (#24)

Author: BD103

.github/workflows/lint.yml

@@ -15,10 +15,10 @@ jobs:
       - uses: actions/setup-python@v2
 
       - name: Install Ballad
-        run: pip install -U ballad
+        run: pip install -U ballad==2.0.0a2
 
       - name: Install Dependencies
-        run: python -m ballad install -D
+        run: python -m ballad install
 
       - name: Check with Black
         run: python -m black --check .