Set upper boundary on version constraint
Set upper boundary on version constraint

Resubmitting, per #137

I'm not sure that this is an improvement over the value prior to https://github.com/aloha/laravel-twilio/commit/0980734612ca48f50684e6298ccad508ed493115 , but it's certainly an improvement over the current value. :)
aloha/laravel-twilio