download this project and then terminal
Downloads/AztecEditor-iOS-develop/Example
carthage update --platform iOS
*** Cloning Gridicons-iOS
*** Checking out Gridicons-iOS at "1.0"
*** xcodebuild output can be found in /var/folders/cf/ff_gvm196wbdr8lxq64t0y9h0000gn/T/carthage-xcodebuild.sWydy2.log
*** Building scheme "Gridicons" in Gridicons.xcworkspace

Build Failed
Task failed with exit code 1:
/usr/bin/xcrun lipo -create /Library/Caches/org.carthage.CarthageKit/DerivedData/12.2_12B45b/Gridicons-iOS/1.0/Build/Intermediates.noindex/ArchiveIntermediates/Gridicons/IntermediateBuildFilesPath/UninstalledProducts/iphoneos/Gridicons.framework/Gridicons /Library/Caches/org.carthage.CarthageKit/DerivedData/12.2_12B45b/Gridicons-iOS/1.0/Build/Products/Release-iphonesimulator/Gridicons.framework/Gridicons -output /Downloads/AztecEditor-iOS-develop/Example/Carthage/Build/iOS/Gridicons.framework/Gridicons

This usually indicates that project itself failed to compile. Please check the xcodebuild log for more details: /var/folders/cf/ff_gvm196wbdr8lxq64t0y9h0000gn/T/carthage-xcodebuild.sWydy2.log