Replace server port by 3001

package.json

@@ -6,7 +6,7 @@
     "lint": "xo",
     "dev": "node server",
     "build": "next build",
-    "start": "NODE_ENV=production node server"
+    "start": "NODE_ENV=production node server -p 3001"
   },
   "dependencies": {
     "@emotion/cache": "^11.7.1",

server.js

@@ -2,7 +2,7 @@ const express = require('express')
 const next = require('next')
 const compression = require('compression')
 
-const port = process.env.PORT || 3000
+const port = process.env.PORT || 3001
 const dev = process.env.NODE_ENV !== 'production'
 const app = next({dev})
 const handle = app.getRequestHandler()