Update actions/checkout action to v4

Author: renovate[bot]

.github/workflows/main.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Check out code
-      uses: actions/checkout@v1
+      uses: actions/checkout@v4
 
     - name: Check for terraform version mismatch
       run: |
@@ -46,7 +46,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           ref: ${{ github.event.pull_request.head.ref }}