Change all protocols which extends class to extend AnyObject instead

[eviltofu]

https://docs.swift.org/swift-book/LanguageGuide/Protocols.html#ID281 states

Class-Only Protocols
You can limit protocol adoption to class types (and not structures or enumerations) by adding the AnyObject protocol to a protocol’s inheritance list.

[hboon]

I think Xcode build or SwiftLint checks for this.