1 line parse CloudEvent from HTTP Request #261

Like Ruby and some other SDKs, it should be 1 line to extract a CloudEvent JSON object from a HTTP request.

• 1 line/function for HTTP -> CloudEvent object
• No constructors needed. No new (unless we're saying new CloudEvent).

Expected

import { Receiver } from "cloudevents";

const event = Receiver.accept(headers, body);

Actual

import { Receiver } from "cloudevents";

const receiver = new Receiver();
const event = receiver.accept(headers, body);

Full Example

For example, this should work in Express:

import { Receiver } from "cloudevents";

const myFunction = (req, res) => {
  const event = Receiver.accept(req.headers, req.body);
  console.log(event.type);
};

This should be updated in the README (currently CloudEvent is unused).

I don't know what the receiver object is really for. Maybe historical. Should be pretty lightweight, right?
Thoughts?