chore(package): update chai-http to version 4.0.0

Author: greenkeeper[bot]

package.json

@@ -41,7 +41,7 @@
   "license": "MIT",
   "devDependencies": {
     "chai": "^4.1.2",
-    "chai-http": "^3.0.0",
+    "chai-http": "^4.0.0",
     "coveralls": "^3.0.0",
     "eslint": "^4.12.1",
     "mocha": "^5.0.0",