Add PromiseKit dependency

- Added PromiseKit dependency

Carthage/Checkouts/PromiseKit/Extensions/Photos/.travis.yml

@@ -0,0 +1,39 @@
+os: osx
+language: objective-c
+matrix:
+  include:
+    - {osx_image: xcode8.3,  env: 'PLAT=iOS   SWFT=3.1  DST="OS=10.3.1,name=iPhone SE"'}
+    - {osx_image: xcode8.3,  env: 'PLAT=tvOS  SWFT=3.1  DST="OS=10.2,name=Apple TV 1080p"'}
+
+    - {osx_image: xcode9.2,  env: 'PLAT=iOS   SWFT=3.2  DST="OS=11.2,name=iPhone SE"'}
+    - {osx_image: xcode9.2,  env: 'PLAT=tvOS  SWFT=3.2  DST="OS=11.2,name=Apple TV"'}
+
+    - {osx_image: xcode9.4,  env: 'PLAT=iOS   SWFT=3.3  DST="OS=11.4,name=iPhone 5s"'}
+    - {osx_image: xcode9.4,  env: 'PLAT=tvOS  SWFT=3.3  DST="OS=11.4,name=Apple TV"'}
+
+    - {osx_image: xcode10,   env: 'PLAT=iOS   SWFT=3.4  DST="OS=12.0,name=iPhone SE"'}
+    - {osx_image: xcode10,   env: 'PLAT=tvOS  SWFT=3.4  DST="OS=12.0,name=Apple TV"'}
+
+    - {osx_image: xcode9.2,  env: 'PLAT=iOS   SWFT=4.0  DST="OS=11.2,name=iPhone SE"'}
+    - {osx_image: xcode9.2,  env: 'PLAT=tvOS  SWFT=4.0  DST="OS=11.2,name=Apple TV"'}
+
+    - {osx_image: xcode9.4,  env: 'PLAT=iOS   SWFT=4.1  DST="OS=11.4,name=iPhone 5s"  TEST=1'}
+    - {osx_image: xcode9.4,  env: 'PLAT=tvOS  SWFT=4.1  DST="OS=11.4,name=Apple TV"   TEST=1'}
+
+    - {osx_image: xcode10,   env: 'PLAT=iOS   SWFT=4.2  DST="OS=12.0,name=iPhone SE"'}
+    - {osx_image: xcode10,   env: 'PLAT=tvOS  SWFT=4.2  DST="OS=12.0,name=Apple TV"'}
+
+cache:
+  directories:
+  - Carthage
+before_install:
+  - carthage bootstrap --cache-builds --no-use-binaries --platform $PLAT --verbose
+install:
+  - xcodebuild -scheme PMKPhotos -target PMKPhotos -quiet -destination "$DST" build SWIFT_VERSION=$SWFT SWIFT_TREAT_WARNINGS_AS_ERRORS=YES
+  - if [[ $TEST == "1" ]]; then
+      xcodebuild -scheme PMKPhotos -target PMKPHTests -quiet -destination "$DST" build;
+    fi
+script:
+  - if [[ $TEST == "1" ]]; then
+      xcodebuild -scheme PMKPhotos -quiet -destination "$DST" test;
+    fi