[+] Add cache for travis-ci

.travis.yml

@@ -1,22 +1,29 @@
 language: objective-c
 osx_image: xcode8.3
+
 branches:
   except:
     - /^dev-(.*)$/
+
+cache:
+  directories:
+    - Carthage
+
 before_install:
-  - brew update && (brew upgrade carthage || true)
-install:
-  - carthage update --platform mac --no-use-binaries
+  - brew update
+  - brew outdated carthage || brew upgrade carthage
+  - carthage bootstrap --platform mac --no-use-binaries --cache-builds
 script:
   - xcodebuild clean build -project AMM.xcodeproj -target AMM
   - xcodebuild test -project AMM.xcodeproj -scheme AMM
+
 before_deploy:
   # package release into dmg
   - release_dir=build/Release
   - release_name=AMM_${TRAVIS_TAG}
   - dmg_path=${release_dir}/${release_name}/${release_name}.dmg
   - mkdir ${release_dir}/${release_name} && mv ${release_dir}/AMM.app $_ && ln -s /Applications $_/
-  - hdiutil create ${dmg_path} -volname release_name -srcfolder ${release_dir}/${release_name}
+  - hdiutil create ${dmg_path} -volname ${release_name} -srcfolder ${release_dir}/${release_name}
 deploy:
   provider: releases
   api_key: