Lint YAML.

.github/workflows/lint.yaml

@@ -1,5 +1,6 @@
+---
 name: Lint
-on:
+"on":
   push:
   pull_request:
   schedule:
@@ -12,11 +13,11 @@ jobs:
     name: Lint markdown
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2.3.3
-    - uses: avto-dev/markdown-lint@v1.4.0
-      with:
-        config: '.github/markdown-lint.yaml'
-        args: './**/*.md'
+      - uses: actions/checkout@v2.3.3
+      - uses: avto-dev/markdown-lint@v1.4.0
+        with:
+          config: '.github/markdown-lint.yaml'
+          args: './**/*.md'
 
   lint-awesome:
     name: Lint Awesome list