Updated Travis CI to Xcode 11.3
diff --git a/.travis.yml b/.travis.yml
index e7b0d3a..ec96ae4 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,3 +1,3 @@
 language: objective-c
 script: ./Run-Tests.sh
-osx_image: xcode10.3
+osx_image: xcode11.3