Add workflow to check formatting using ruff

Author: johannaengland

.github/workflows/format.yml

@@ -0,0 +1,18 @@
+name: Verify formatting
+
+on:
+  push:
+    branches: master
+  pull_request:
+
+jobs:
+  ruff:
+    runs-on: ubuntu-latest
+    name: Verify Python formatting
+    steps:
+    - uses: actions/checkout@v4
+
+    - uses: astral-sh/ruff-action@v3
+      with:
+        version: "0.11.9"
+        args: "format --check"