XCFramework support

[mateuszszklarek]

Hi @kzaher! First for all thanks for your amazing works - I'm big fan of reactive approach in general 👍

I've added support for XCFramework - there was an issue to integrate RxFeedback via Carthage using --use-xcframeworks flag - I'm attaching logs that I've encountered during migration to xcframework.

/MyProject/Carthage/Checkouts/RxFeedback/Sources/RxFeedback/Feedbacks.swift:9:8: error: no such module 'RxCocoa'
import RxCocoa
       ^
** ARCHIVE FAILED **
The following build commands failed:
	CompileSwift normal armv7
	CompileSwiftSources normal armv7 com.apple.xcode.tools.swift.compiler
	CompileSwift normal arm64
	CompileSwiftSources normal arm64 com.apple.xcode.tools.swift.compiler
(4 failures)

• fix the issue with integrating via Carthage and using --use-xcframeworks flag
• use all dependencies as *.xcframework instead of *.framework
• fix CI for Carthage integration

This PR solves this issue - let me know if there is anything that should be updated and I forgot about it 👍 🚀