Update .drone.yml

.drone.yml

@@ -17,6 +17,10 @@ steps:
     - ssh-keyscan -H git.ericxliu.me > $HOME/.ssh/known_hosts
     - git clone --branch gitea-pages git@git.ericxliu.me:eric/ericxliu-me.git /output
     - find /output -mindepth 1 -not -regex "^.*\/.git.*" -delete
+- name: submodules
+  image: alpine/git
+  commands:
+  - git submodule update --init --recursive
 - name: build
   image: plugins/hugo
   volumes: