add lint.yml

.github/workflows/lint.yml

@@ -0,0 +1,27 @@
+name: Lint
+
+on: [push, pull_request]
+
+jobs:
+
+  lint:
+    name: Check for lint
+    # We want to run on external PRs, but not on our own internal PRs as they'll be run
+    # by the push to the branch. Without this if check, checks are duplicated since
+    # internal PRs match both the push and pull_request events.
+    if:
+      github.event_name == 'push' || github.event.pull_request.head.repo.full_name !=
+      github.repository
+
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Python 3.11
+        uses: actions/setup-python@v4
+        with:
+          python-version: 3.11
+
+      - name: Lint
+        run: |
+          pip install nox
+          nox -s lint -- --no-skip