fix ruff version in CI

Author: yungwine

.github/workflows/tests.yml

@@ -30,7 +30,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install ruff pytest pytest-mock
+          pip install ruff==0.15.22 pytest pytest-mock
 
       - name: Run Ruff
         run: |