dont use branch

Author: kevinjqliu

.github/workflows/check-md-link.yml

@@ -39,7 +39,7 @@ jobs:
   markdown-link-check:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@61b9e3751b92087fd0b06925ba6dd6314e06f089 # master
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
       with:
         persist-credentials: false
     - uses: tcort/github-action-markdown-link-check@e7c7a18363c842693fadde5d41a3bd3573a7a225 # v1.1.2