Compatibility with latest NewRelic Agent API

Addressing Issue wix-incubator#23 facebook/react-native#21498

If you follow the guidance given wix-incubator#23 (comment) then you can get this working. But if you need to build your app in a CI/CD environment, then no way to edit your node modules.

This change brings this bridge in line with the current NewRelic agent.

ios/RNNewRelic/RNNewRelic.m

@@ -13,7 +13,7 @@ @implementation RNNewRelic
 RCT_EXPORT_MODULE();
 
 RCT_EXPORT_METHOD(send: (NSString*)name :(NSDictionary*)args){
-  [NewRelicAgent recordEvent:name attributes:args];
+  [NewRelicAgent recordCustomEvent:name attributes:args];
 }