modify ci

.codechina-ci.yml

@@ -9,7 +9,8 @@ pages:
   - yarn install # npm install
   - yarn add -D vuepress # npm install -D vuepress
   - yarn docs:build # npm run docs:build
-  - cp robots.txt public/
+  - mkdir public
+  - cp robots.txt public
   - mv docs/.vuepress/dist public
  artifacts:
    paths: