Support the single argument options only config API

`Raven.config` supports calling it with only the configuration object if
you'd like the DSN to be pulled from environment variables

https://github.com/getsentry/raven-node/blob/6ce861f9f3fabdeba37013ff1d7dedc3eb6f7a80/lib/client.js#L44-L47

types/raven/index.d.ts

@@ -10,6 +10,7 @@ import { IncomingMessage, ServerResponse } from 'http';
 import { EventEmitter } from 'events';
 
 export const version: string;
+export function config(options?: ConstructorOptions): Client;
 export function config(dsn?: string | false, options?: ConstructorOptions): Client;
 export function wrap<T>(func: () => T): () => T;
 export function wrap<T>(options: any, func: () => T): () => T;

types/raven/raven-tests.ts

@@ -9,6 +9,10 @@ Raven.config(dsn, {
     autoBreadcrumbs: false,
 });
 console.log(Raven.version);
+
+Raven.config({
+    release: 'foobar'
+});
 Raven.config(dsn).install({ captureUnhandledRejections: true });
 client.setContext({});
 client.on('logged', () => { });