node-proxy capitalize lower case headers

webpack.config.js

var http = require('http');
var setHeader = http.OutgoingMessage.prototype.setHeader;
http.OutgoingMessage.prototype.setHeader = function() {
	var match, submatch;
	arguments[0] = arguments[0].replace(/\b(\w)/g, function(match, submatch) {
		return submatch ? submatch.toUpperCase() : "";
	});
	setHeader.apply(this, arguments);
};