fix: only use tag 'latest' in main branch image build

ci-templates/build.yml

@@ -15,12 +15,13 @@
     name: gcr.io/kaniko-project/executor:debug
     entrypoint: [""]
   script:
-    - /kaniko/executor --context "${CI_PROJECT_DIR}" --dockerfile "${CI_PROJECT_DIR}/Dockerfile" --destination "${CI_REGISTRY_IMAGE}:$APP_VERSION"
+    - export DOCKER_TAG=$APP_VERSION
     - |
       if [ "$CI_COMMIT_REF_NAME" = "main" ]; then
         echo "Pushing Docker image with tag 'latest'"
-        /kaniko/executor --context "${CI_PROJECT_DIR}" --dockerfile "${CI_PROJECT_DIR}/Dockerfile" --destination "${CI_REGISTRY_IMAGE}:latest"
+        export DOCKER_TAG=latest
       fi
+    - /kaniko/executor --context "${CI_PROJECT_DIR}" --dockerfile "${CI_PROJECT_DIR}/Dockerfile" --destination "${CI_REGISTRY_IMAGE}:$APP_VERSION"
 
 .angular_build:
   extends: .default