add normalization enforcement workflow step

.github/workflows/yaml-normalization.yml

@@ -0,0 +1,24 @@
+name: YAML normalization
+on:
+  push:
+    paths:
+      - 'data/**.yaml'
+    branches:
+      - main
+  pull_request:
+    paths:
+      - 'data/**.yaml'
+    branches:
+      - main
+jobs:
+  ensure-yaml-normalization:
+    name: Ensure YAML files are normalized
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Normalize
+        uses: mikefarah/yq@master
+        with:
+          cmd: |
+            scripts/normalize-all-yaml.sh
+            git diff --quiet