ci: validate YAML

.github/workflows/validate.yml

@@ -0,0 +1,20 @@
+name: CI
+on:
+  pull_request:
+  push:
+    branches: [main]
+
+jobs:
+  validate:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - name: Validate YAML
+        uses: nwisbeta/validate-yaml-schema@v1.0.3
+        with:
+          yamlSchemasJson: |
+            {
+              "https://json.schemastore.org/github-action.json": ["action.yml"]
+            }