Remove requiresPort dependency

location.host is directly parsed from the full URL, so the
"concatenate host and port" branch was never taken.

lib/cors-anywhere.js

@@ -8,7 +8,6 @@ var net = require('net');
 var url = require('url');
 var regexp_tld = require('./regexp-top-level-domain');
 var getProxyForUrl = require('proxy-from-env').getProxyForUrl;
-var requiresPort = require('requires-port');
 
 var help_file = __dirname + '/help.txt';
 var help_text;
@@ -83,9 +82,7 @@ function proxyRequest(req, res, proxy) {
     prependPath: false,
     target: location,
     headers: {
-      host: requiresPort(location.port, location.protocol) && !/:\d*$/.test(location.host) ?
-        location.host + ':' + location.port :
-        location.host,
+      host: location.host,
     },
   };
   var proxyThroughUrl = req.corsAnywhereRequestState.getProxyForUrl(location.href);