Fix carthage build

[gilroykilroy]

Fix carthage build by checking in the generated Swift header file into the project. Perhaps some tweaking of search paths would solve the problem too but I could not figure that out.

[Lex-Nagtegaal]

when will this pull request be merged?

[yoichitgy]

Thank you for making the PR😃 and sorry for taking too long to respond🙇‍♂️

I'm not sure we still see the issue when using Carthage.

• carthage-build.sh made in PR feature(xcode12.5): update for a new xcode version and swift 5 #156 might help users of Carthage.
• Support of xcframework might be alternative.
• Not sure but we'll see possibility that Carthage itself fixed the issue.

[mpdifran]

Yeah I don't think this is necessary. The included ./carthage-build.sh helps get around the build issue when not using xcframeworks, and we'll add xcframework support in the next major version.