chore(deps): update terraform-linters/setup-tflint action to v6

Author: renovate[bot]

sync-root/.github/workflows/terraform-validation.yaml

@@ -25,7 +25,7 @@ jobs:
         uses: hashicorp/setup-terraform@v3
 
       - name: Setup Terraform Linters
-        uses: terraform-linters/setup-tflint@v4
+        uses: terraform-linters/setup-tflint@v6
         with:
           github_token: ${{ github.token }}