message: docs(Icons): add contribution guide
diff: @@ -17,16 +17,3 @@ pnpm add @vant/icons
  - [Usage in Vue](https://youzan.github.io/vant/#/zh-CN/icon)
  - [Usage in Weapp](https://youzan.github.io/vant-weapp/#/icon)
  -
  -## Contribution
  -
  -### Update Icons
  -
  -1. Update assets/icons.sketch
  -2. Make a Pull Request
  -
  -### Add New Icon
  -
  -1. Add new icon to assets/icons.sketch
  -2. Add icon name to src/config.js
  -3. Make a Pull Request
  