Add support for CocoaPods

[virginiapujols-yml]

Introduction

Add support for CocoaPods; a dependency manager for Swift and Objc

Purpose

Our aim is to provide support for CocoaPods as it is useful for React Native projects to have access to the library.

Scope

Included a new file named YMatterType.podspec

[mpospese]

I would really like to find some other way to enable this use in React Native. I don't think we want to add cocoapods support back because it complicates our release system.

Action	Cocoapods release	SPM release
push tag	❌	✅
update .podspec	✅	❌
pod repo push to update cocoapods directory	✅	❌

Especially the bit about updating the .podspec file means creating an additional PR to bump the version in that file to match the tag. Whereas for SPM all we need do is push a tag to our own repo.