Update CI workflow to specify source directory for linting

- Modified the CI configuration in `ci.yml` to change the linting command from checking the entire `src` directory to specifically targeting the `duty_teller` package and `tests`.
- This change enhances the accuracy of linting by focusing on relevant code areas, improving code quality checks during the CI process.

.gitea/workflows/ci.yml

@@ -28,7 +28,7 @@ jobs:
 
       - name: Lint with Ruff
         run: |
-          ruff check src tests
+          ruff check duty_teller tests
 
       - name: Run tests
         env: