fix(ci): remove unused DATE build argument from Docker build process

.gitlab-ci.yml

@@ -36,7 +36,7 @@ workflow:
       echo "Image tag: $IMAGE_TAG"
     - echo "Logging into Harbor..."
     - echo "$HARBOR_PASSWORD" | docker login -u "$HARBOR_USERNAME" --password-stdin "$HARBOR_SERVICE"
-    - docker build -f Dockerfile --build-arg VERSION="${VERSION}" --build-arg COMMIT="${COMMIT}" --build-arg DATE="${DATE}" -t "$HARBOR_SERVICE/$HARBOR_REGISTRY/sub2api:${IMAGE_TAG}" .
+    - docker build -f Dockerfile --build-arg VERSION="${VERSION}" --build-arg COMMIT="${COMMIT}" -t "$HARBOR_SERVICE/$HARBOR_REGISTRY/sub2api:${IMAGE_TAG}" .
     - docker push "$HARBOR_SERVICE/$HARBOR_REGISTRY/sub2api:${IMAGE_TAG}"
     - docker rmi "$HARBOR_SERVICE/$HARBOR_REGISTRY/sub2api:${IMAGE_TAG}" || true
 
@@ -46,7 +46,6 @@ sub2api:
   variables:
     VERSION: "${CI_COMMIT_TAG:-}"
     COMMIT: "${CI_COMMIT_SHA}"
-    DATE: "$(date -u +%Y-%m-%dT%H:%M:%SZ)"
   rules:
     - if: $CI_COMMIT_TAG =~ /^sub2api\/v/
       when: always