[AIT-287] Add the RESUMED flag to onChannelAttached#9

lawrence-forooghian wants to merge 2 commits intomainably/ably-cocoa-plugin-support:mainfrom

AIT-287-add-RESUMED-to-onChannelAttachedably/ably-cocoa-plugin-support:AIT-287-add-RESUMED-to-onChannelAttachedCopy head branch name to clipboard