Added requiresMainQueueSetup to prevent warning and future side-effects

[djalmaaraujo]

New versions of react will require requiresMainQueueSetup method. Here's the warning:

Module CodePush requires main queue setup since it overrides `constantsToExport` but doesn't implement `requiresMainQueueSetup. In a future release React Native will default to initializing all native modules on a background thread unless explicitly opted-out of.

[max-mironov]

@djalmaaraujo Thank you for contribution, looks good, merging it!