Updated example template in contributing.md (#11968)

contributing.md

@@ -143,7 +143,7 @@ Deploy the example using [Vercel](https://vercel.com/now):
 Execute [`create-next-app`](https://github.com/zeit/next.js/tree/canary/packages/create-next-app) with [npm](https://docs.npmjs.com/cli/init) or [Yarn](https://yarnpkg.com/lang/en/docs/cli/create/) to bootstrap the example:
 
 ```bash
-npx create-next-app --example DIRECTORY_NAME DIRECTORY_NAME-app
+npm init next-app --example DIRECTORY_NAME DIRECTORY_NAME-app
 # or
 yarn create next-app --example DIRECTORY_NAME DIRECTORY_NAME-app
 ```