carthage update 失败如何处理？
SwiftWeather git:(master) ✗ carthage update
*** Fetching SwiftyJSON
*** Fetching Alamofire
*** Checking out Alamofire at "1.1.2"
*** Checking out SwiftyJSON at "2.1.3"
*** xcodebuild output can be found in /var/folders/r9/5538mr9s1mg7rc6qb510q4fw0000gn/T/carthage-xcodebuild.Oru4MX.log
*** Building scheme "Alamofire" in Alamofire.xcworkspace
** BUILD FAILED **
The following build commands failed:
Check dependencies
(1 failure)
