Remove Cocoapods Support #607

Cocoapods will move to read-only on December 2, 2026 (blogpost).

With that in mind, we should remove Cocoapods support and encourage clients to migrate before said deadline. The following will be required:

• Write, test, and publish migration instructions.
• Notify library users of the impending deprecation.
• Stage changes that remove support.

Additional:
Firebase has published instructions & their own pre-deadline here, and we'll likely be able to utilize the same.