update sw.js

@@ -15,11 +15,11 @@ const NAME_CACHE_PREFIX = 'yoho-cache';
 const precaches = [
     {
         url: '/offline.html',
-        rivision: 'offline-rivision-0.0.2'
+        revision: 'offline-revision-0.0.2'
     },
     {
         url: '//cdn.yoho.cn/pwa/404.png',
-        rivision: '404-rivision-0.0.1'
+        revision: '404-revision-0.0.1'
     }].concat(self.__precacheManifest || []);
 
 self.workbox.precaching.precacheAndRoute(precaches);