docs: unify deploy script name (vuejs#88)

Author: miyaoka

docs/guide/deploy.md

@@ -33,14 +33,14 @@ You can run this script in your CI setup to enable automatic deployment on each
 ``` json
 {
  "scripts": {
- "build-docs": "vuepress build docs"
+ "docs:build": "vuepress build docs"
  }
 }
 ```
 
 2. On Netlify, setup up a new project from GitHub with the following settings:
 
- - **Build Command:** `npm run build-docs` or `yarn build-docs`
+ - **Build Command:** `npm run docs:build` or `yarn docs:build`
  - **Publish directory:** `docs/.vuepress/dist`
 
 3. Hit the deploy button!