emit proxyReqWs event when appropriate

It seems like we use the emit function to trigger potential event
handlers registered, but from what I understand we should do this
differently depending on either proxied web requests and proxied web
socket requests.

ref: https://github.com/http-party/node-http-proxy#listening-for-proxy-events

Author: consideRatio

lib/configproxy.js

@@ -510,7 +510,12 @@ class ConfigurableProxy extends EventEmitter {
         return;
       }
 
-      that.emit("proxyRequest", req, res);
+      if (kind === "web") {
+        that.emit("proxyRequest", req, res);
+      }
+      else {
+        that.emit("proxyRequestWs", req, res, args[2]);
+      }
       var prefix = match.prefix;
       var target = match.target;
       that.log.debug("PROXY %s %s to %s", kind.toUpperCase(), req.url, target);