chore(package): update @types/mocha to version 5.2.1

Closes #94

Author: greenkeeper[bot]

package.json

@@ -49,7 +49,7 @@
   "devDependencies": {
     "@types/chai": "^4.1.2",
     "@types/minimist": "^1.2.0",
-    "@types/mocha": "^2.2.48",
+    "@types/mocha": "^5.2.1",
     "@types/node": "^9.4.6",
     "chai": "^4.1.2",
     "del": "^3.0.0",