Replace class constraint with AnyObject

[yhkaplan]

Pretty insignificant, but the recommended practice in Swift now is to use AnyObject instead of class, and recently there have been motions toward a new reference type (actor) that the class naming makes a little unclear, while AnyObject is more of a generic and all-encompassing term for reference types. Also, the class constraint typealias may be removed in future versions of Swift.

ref: https://github.com/apple/swift-evolution/blob/master/proposals/0156-subclass-existentials.md#class-and-anyobject

[apollo-cla]

@yhkaplan: Thank you for submitting a pull request! Before we can merge it, you'll need to sign the Apollo Contributor License Agreement here: https://contribute.apollographql.com/

[AnthonyMDev]

LGTM! Thanks for the clean up!

[cltnschlosser]

With Xcode 12.5 in RC now, it would be nice to get a version released with this warning fixed. Thanks!

[designatednerd]

Hey - I'm working on some tests for some web socket stuff that was merged earlier today before I do a release but will try to get this out early next week.

[cltnschlosser]

Hey - I'm working on some tests for some web socket stuff that was merged earlier today before I do a release but will try to get this out early next week.

Great, thanks!

[designatednerd]

Guh, apple, why you gotta release Xcode on a Monday? will cut a release tomorrow morning.