Update actions/checkout action to v4

Author: renovate[bot]

.github/workflows/terraform.yaml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 10
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: hashicorp/setup-terraform@v2
       - run: make
       - uses: int128/update-generated-files-action@v2
@@ -24,6 +24,6 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 10
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: terraform-docs/gh-actions@v1
       - uses: int128/update-generated-files-action@v2