fix: upgrade chai from 4.1.2 to 4.2.0

Snyk has created this PR to upgrade chai from 4.1.2 to 4.2.0.

See this package in npm:
https://www.npmjs.com/package/chai

See this project in Snyk:
https://app.snyk.io/org/postman/project/a5c111c7-1bc9-4d89-849d-6732a81fc539?utm_source=github&utm_medium=upgrade-pr

Author: snyk-bot

package-lock.json

@@ -129,7 +129,7 @@
   "author": "Postman Labs <help@getpostman.com>",
   "license": "Apache-2.0",
   "devDependencies": {
-    "chai": "4.1.2",
+    "chai": "4.2.0",
     "editorconfig": "0.15.3",
     "eslint": "5.16.0",
     "eslint-plugin-jsdoc": "3.8.0",