Switch to pyproject.toml, and to ruff from flake8

.github/workflows/test.yml

@@ -32,9 +32,9 @@ jobs:
       - name: wheel
         run: |
           python -m pip install -e .[tests]
-      - name: flake8
+      - name: ruff
         run: |
-          flake8 pytiled_parser
+          ruff check pytiled_parser
       - name: mypy
         if: success() || failure()
         run: |