Rename a reference to the combined context
Rename a reference to the combined context

In #158 the event and context arguments to the callback got combined into one.
The documentation was still referring to the event object, which is no longer present.

bkeepers/PRobot,pholleran-org/probot,pholleran-org/probot,bkeepers/PRobot,probot/probot,pholleran-org/probot,probot/probot,probot/probot