ci: Add test-validate to CI pipeline

.gitlab-ci.yml

@@ -23,6 +23,7 @@ stages:
   - lint
   - build
   - test-init
+  - test-validate
   - test-plan
   - test-apply
   - test-destroy
@@ -73,6 +74,14 @@ test-init:
     - export DEBUG_OUTPUT=true
     - gitlab-terraform init
 
+test-validate:
+  extends:
+    - .test
+    - .versions
+  stage: test-validate
+  script:
+    - gitlab-terraform validate
+
 test-plan:
   extends:
     - .test