Add missing fields to APIGatewayProxyRequestEvent.ProxyRequestContext

[Shola Daniel Babalola]

Per AWS documentation, requestTimeEpoch and other fields should be in ProxyRequestContext
https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-lambda-proxy-integrations.html

[Mark Sailes]

Awaiting v4 release.