fix 'sntp' async function on circle

regou · web-flow · commit 6c0d09a34259 · 2018-03-12T17:00:12.000+08:00
https://circleci.com/gh/vuejs/vue-rx/35
diff --git a/circle.yml b/circle.yml
@@ -1,3 +1,3 @@
 machine:
   node:
-    version: 6
+    version: 8
