Bumped actions/checkout to 6.0.2

Author: adamlui

.github/workflows/link-checker.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6.0.2
 
       - name: Check links
         uses: lycheeverse/lychee-action@v2