change travis to xcode9.2

.travis.yml

@@ -2,7 +2,7 @@
 # * http://www.objc.io/issue-6/travis-ci.html
 # * https://github.com/supermarin/xcpretty#usage
 
-osx_image: xcode8.2
+osx_image: xcode9.2
 language: objective-c
 cache: cocoapods
 podfile: Example/Podfile
@@ -12,5 +12,4 @@ before_install:
 - pod setup
 - pod install --project-directory=Example
 script:
-- set -o pipefail && xcodebuild test -workspace Example/ResourcePackage.xcworkspace -scheme ResourcePackage-Example -sdk iphonesimulator10.2 -destination 'platform=iOS Simulator,name=iPhone 7,OS=10.1' ONLY_ACTIVE_ARCH=NO | xcpretty
 - pod lib lint