doc: fix broken example links (#667)

* Fix broken example links

* fix create react app example link

docs/docs/01-installation.md

@@ -162,7 +162,7 @@ That's all!
 
 ## 3. webpack: Copy whole Cesium files and load Cesium in HTML
 
-See also: [example project](https://github.com/reearth/resium/tree/main/example/webpack)
+See also: [example project](https://github.com/reearth/resium/tree/main/examples/webpack)
 
 ### 3-1. Install webpack plugins
 
@@ -233,7 +233,7 @@ Note: If `publicPath` in webpack config is changed, `CESIUM_BASE_URL` may have t
 
 In this way, imported and used Cesium source codes are bundled to your app's source code with webpack.
 
-See also: [example project](https://github.com/reearth/resium/tree/main/example/webpack2) and [Cesium official example](https://github.com/AnalyticalGraphicsInc/cesium-webpack-example)
+See also: [example project](https://github.com/reearth/resium/tree/main/examples/webpack2) and [Cesium official example](https://github.com/AnalyticalGraphicsInc/cesium-webpack-example)
 
 ### 4-1. Install webpack plugins and loaders
 
@@ -329,7 +329,7 @@ import "cesium/Widgets/widgets.css";
 
 [Vite](https://vitejs.dev/) is one of next generation JavaScript bundler. [vite-plugin-cesium](https://github.com/nshen/vite-plugin-cesium) is recommended to use Cesium with Vite.
 
-See also: [example project](https://github.com/reearth/resium/tree/main/example/vite)
+See also: [example project](https://github.com/reearth/resium/tree/main/examples/vite)
 
 Init a new vite project (select "react"):