Bump Xcode version for Travis

fulldecent · fulldecent · commit c690d2609f14 · 2017-04-15T03:32:14.000+08:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,5 +1,5 @@
 language: objective-c
-osx_image: xcode7.3
+osx_image: xcode8.3
 env:
   global:
   - LC_CTYPE=en_US.UTF-8
