Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/documentation.yml

@@ -25,7 +25,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           ref: ${{ github.event.pull_request.head.ref }}
 

.github/workflows/linter.yml

@@ -28,7 +28,7 @@ jobs:
     steps:
 
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
 

.github/workflows/terraform.yml

@@ -35,7 +35,7 @@ jobs:
         run: echo "branch=${GITHUB_HEAD_REF}" >> "$GITHUB_OUTPUT"
 
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           ref: ${{ steps.branch.outputs.branch }}