Update dependency mocha to v5.2.0 (#343)

Author: renovate[bot]

package-lock.json

@@ -46,7 +46,7 @@
     "geckodriver": "1.11.0",
     "istanbul": "0.4.5",
     "mkdirp": "0.5.1",
-    "mocha": "5.0.0",
+    "mocha": "5.2.0",
     "portfinder": "1.0.13",
     "selenium-assistant": "5.3.0",
     "semver": "5.4.1",