chore(deps): update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/lighthouse.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Use Node.js 22.x
         uses: actions/setup-node@v5
         with: