Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/format.yml

@@ -9,7 +9,7 @@ jobs:
 
     steps:
       - name: Checkout project
-        uses: actions/checkout@v3
+        uses: actions/checkout@v6
         with:
           ref: ${{ github.head_ref }}
           fetch-depth: 0

.github/workflows/lighthouse.yml

@@ -12,7 +12,7 @@ jobs:
 
     steps:
       - name: Checkout project
-        uses: actions/checkout@v3
+        uses: actions/checkout@v6
         with:
           ref: ${{ github.head_ref }}
           fetch-depth: 0