Mount probot handler to the root URL

Author: weirdan

src/index.ts

@@ -2,7 +2,7 @@ import { createNodeMiddleware, createProbot } from 'probot'
 import app from './app'
 import * as functions from '@google-cloud/functions-framework'
 
-const middleware = createNodeMiddleware(app, { probot: createProbot() })
+const middleware = createNodeMiddleware(app, { probot: createProbot(), webhooksPath: '/' })
 functions.http(
   'probotApp',
   async (req, res) => {