Fix typo in deployment docs (facebook#6881)

Typo : preache => precache

Author: david-cho-lerat-HL2

docusaurus/docs/deployment.md

@@ -90,7 +90,7 @@ service worker navigation routing can be configured or disabled by
 [`eject`ing](available-scripts.md#npm-run-eject) and then modifying the
 [`navigateFallback`](https://github.com/GoogleChrome/sw-precache#navigatefallback-string)
 and [`navigateFallbackWhitelist`](https://github.com/GoogleChrome/sw-precache#navigatefallbackwhitelist-arrayregexp)
-options of the `SWPreachePlugin` [configuration](../config/webpack.config.prod.js).
+options of the `SWPrecachePlugin` [configuration](../config/webpack.config.prod.js).
 
 When users install your app to the homescreen of their device the default configuration will make a shortcut to `/index.html`. This may not work for client-side routers which expect the app to be served from `/`. Edit the web app manifest at [`public/manifest.json`](public/manifest.json) and change `start_url` to match the required URL scheme, for example: