Add Carthage shield to README
Add Carthage shield to README
czechboy0/XcodeServerSDK,colemancda/XcodeServerSDK,czechboy0/XcodeServerSDK,drewcrawford/XcodeServerSDK,colemancda/XcodeServerSDK,colemancda/XcodeServerSDK,drewcrawford/XcodeServerSDK,drewcrawford/XcodeServerSDK,cojoj/XcodeServerSDK,cojoj/XcodeServerSDK