chore(release): 2.1.2 (#126)
* Fix(nodejs/event_dispatcher): update error/resp handlers (#123)
- (nodejs) Prevent crash when `http`/`https` emits an error by adding an 'error' listener
- (nodejs) Fix `requestCallback` to conform to its role as a 'response' listener; notably, ensure it is called when the first argument is interpeted as the `http.IncomingMessage`, and _not_ called in the event of an error (as expected by `Optimizely#_sendImpressionEvent`/`Optimizely#track`).
Tested that this version (as 2.1.2-0) _does_ emit the messages expected in the demo app.
Fixes #122
Fixes #124
