ApiGwV2HttpEvent: added requestId

[mcoup]

Description of changes:

• Added requestId field as it's provided by http gateway V2 (see json below).

Tested on apigw in us-west-2:

public class TestHandler implements RequestHandler<APIGatewayV2HTTPEvent, String> {

  @Override
  public String handleRequest(APIGatewayV2HTTPEvent apiGatewayV2HTTPEvent, Context context) {
    System.out.println(apiGatewayV2HTTPEvent.getRequestContext().getRequestId());
    return null;
  }
}

Original request from apigw:

{
  "version": "2.0",
  "routeKey": "ANY /printer",
  "rawPath": "/printer",
  "rawQueryString": "",
  "headers": {
    "accept": "*/*",
    "content-length": "0",
    "host": "abcdef.execute-api.us-west-2.amazonaws.com",
    "user-agent": "curl/7.71.1",
    "x-amzn-trace-id": "Root=1-60583e5a-1f74381240de6ded5a65dbd0",
    "x-forwarded-for": "127.0.0.1",
    "x-forwarded-port": "443",
    "x-forwarded-proto": "https"
  },
  "requestContext": {
    "accountId": "123456789012",
    "apiId": "abcdef",
    "domainName": "abcdef.execute-api.us-west-2.amazonaws.com",
    "domainPrefix": "abcdef",
    "http": {
      "method": "GET",
      "path": "/printer",
      "protocol": "HTTP/1.1",
      "sourceIp": "127.0.0.1",
      "userAgent": "curl/7.71.1"
    },
    "requestId": "fakeRequestid=",  <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
    "routeKey": "ANY /printer",
    "stage": "$default",
    "time": "22/Mar/2021:06:51:06 +0000",
    "timeEpoch": 1616395866990
  },
  "isBase64Encoded": false
}

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[msailes]

I tested this on AWS. 👍

[carlzogh]

Aligns with documented schema https://docs.aws.amazon.com/lambda/latest/dg/services-apigateway.html - LGTM, thanks for your contribution!