upgrade travis xcode version

nightpool · nightpool · commit b59c76a911bb · 2020-07-16T13:21:39.000-04:00
diff --git a/.travis.yml b/.travis.yml
@@ -9,7 +9,7 @@ matrix:
   include:
     - rvm: 2.6
       os: osx
-      osx_image: xcode9.4.1
+      osx_image: xcode12
   fast_finish: true
 addons:
   apt:
