Update .gitlab-ci.yml

.gitlab-ci.yml

-image: node:4.2.2
+image: node:8.11.2
 
-pages:
-  cache:
+cache:
     paths:
-    - node_modules/
+        - node_modules/
 
-  script:
-  - npm install hexo-cli -g
-  - npm install
-  - hexo deploy
-  artifacts:
-    paths:
-    - public
-  only:
-  - master
+variables:
+    GIT_SUBMODULE_STRATEGY: recursive
+
+before_script:
+    - npm install hexo-cli -g
+    - npm install
+
+pages:
+    script:
+        - hexo generate
+    artifacts:
+        paths:
+            - public
+    only:
+        - master