added xcode 9 and 9.1 coz 8 and 8.1 links to 8.3

diff --git a/.travis.yml b/.travis.yml
index 22f6ed7ba34afb6c6d0d45c1c8a6d5c46e490d04..eed0f8e512c72cb3657a75d8ba2ea3b92212627a 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,11 +10,11 @@ matrix:
     - os: osx
       osx_image: xcode7.3      # OS X 10.11
     - os: osx
-      osx_image: xcode8     # OS X 10.11
+      osx_image: xcode8.3   # OS X 10.12
     - os: osx
-      osx_image: xcode8.1   # OS X 10.12
+      osx_image: xcode9     # OS X 10.13
     - os: osx
-      osx_image: xcode8.3   # OS X 10.12
+      osx_image: xcode9.1   # OS X 10.13.1
     - os: linux
       dist: trusty
       sudo: required