Update chai from 3.5.0 to 4.1.2

Author: dependencies-bot

package.json

@@ -45,7 +45,7 @@
     "oc"
   ],
   "devDependencies": {
-    "chai": "3.5.0",
+    "chai": "4.1.2",
     "chalk": "^2.1.0",
     "glob": "^7.1.2",
     "husky": "^0.14.3",