chore(package): update http-proxy-middleware to version 0.18.0 (#2890)

package.json

@@ -117,7 +117,7 @@
     "gulp-watch": "~5.0.0",
     "gulp-xslt": "~3.0.0",
     "html-minifier": "~3.5.6",
-    "http-proxy-middleware": "~0.17.4",
+    "http-proxy-middleware": "~0.18.0",
     "js-beautify": "~1.7.4",
     "jsesc": "~2.5.1",
     "karma": "~2.0.0",