Fix incorrect workflow

Author: thibmaek

.github/workflows/ci.yaml

@@ -4,5 +4,7 @@ on: push
 
 jobs:
   lint_md:
-    - uses: actions/checkout@main
-    - uses: gaurav-nelson/github-action-markdown-link-check@v1
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@main
+      - uses: gaurav-nelson/github-action-markdown-link-check@v1