actually add the linter workflow

.github/workflows/lint.yml

@@ -0,0 +1,15 @@
+name: Lint Python code with ruff
+on: [push, pull_request]
+
+jobs:
+  lint:
+    name: Lint Python code with ruff
+    runs-on: ubuntu-latest
+    if:
+      github.event_name == 'push' || github.event.pull_request.head.repo.full_name != github.repository
+
+    steps:
+      - uses: actions/checkout@v3
+      - run: pip install --user ruff
+      - run: ruff --format=github --target-version=py37
+                  --ignore=E101,E501,E401,E402,E701,E703,E711,E712,E713,E714,E721,E722,E731,E741,F401,F403,F405,F601,F811,F841,F901 .