Update .travis.yml

Author: lm2343635

.travis.yml

@@ -2,7 +2,7 @@
 # * https://www.objc.io/issues/6-build-tools/travis-ci/
 # * https://github.com/supermarin/xcpretty#usage
 
-osx_image: xcode10.2
+osx_image: xcode11.1
 language: objective-c
 cache: cocoapods
 podfile: Example/Podfile