[Swift4] Petstore integration test failed

[wing328]

Description

If I run the following command

cd samples/client/petstore/swift4/default/SwaggerClientTests
./run_xcodebuild.sh

I got the following errors:

** TEST BUILD FAILED **


The following build commands failed:
	CompileSwift normal x86_64 /tmp/sw2/swagger-codegen/samples/client/petstore/swift4/default/PetstoreClient/Classes/Swaggers/Models/Cat.swift
	CompileSwift normal x86_64 /tmp/sw2/swagger-codegen/samples/client/petstore/swift4/default/PetstoreClient/Classes/Swaggers/Models/Dog.swift
	CompileSwift normal x86_64 /tmp/sw2/swagger-codegen/samples/client/petstore/swift4/default/PetstoreClient/Classes/Swaggers/Models/EnumArrays.swift
	CompileSwift normal x86_64 /tmp/sw2/swagger-codegen/samples/client/petstore/swift4/default/PetstoreClient/Classes/Swaggers/APIs/FakeAPI.swift
	CompileSwiftSources normal x86_64 com.apple.xcode.tools.swift.compiler
(5 failures)

Swagger-codegen version

Latest master

Suggest a fix/enhancement

If anyone wants to help fix the issue, please reply to let us know.

[d-date]

@wing328 I think it was fixed with #6921 and passed CI with #7821 so that we can close this issue