Add support to pass in options for aws-lambda-mock-context

[hueezer]

I'm running into issues where the mock context times out after 3 seconds (which is the default). It would be great to be able to pass in options (such as timeout) to the aws-lambda-mock-context dependency. https://www.npmjs.com/package/aws-lambda-mock-context

[hoegertn]

This is released with version 1.2.3