chore: bump docusaurus to 2.1.0 (#91)

升级 docusaurus 到 2.1.0

- https://github.com/facebook/docusaurus/releases/tag/v2.0.0
- https://github.com/facebook/docusaurus/releases/tag/v2.1.0

```release-note
none
```

sidebars.js

@@ -9,6 +9,7 @@
  Create as many sidebars as you want.
  */
 
+ /** @type {import('@docusaurus/plugin-content-docs').SidebarsConfig} */
 module.exports = {
   // By default, Docusaurus generates a sidebar from the docs folder structure
   // tutorialSidebar: [{type: 'autogenerated', dirName: '.'}],