Update dependency mocha to v6.2.3

Author: renovate-bot

package.json

@@ -47,7 +47,7 @@
   "devDependencies": {
     "coveralls": "3.0.6",
     "istanbul": "0.4.5",
-    "mocha": "~6.1.4",
+    "mocha": "6.2.3",
     "mocha-lcov-reporter": "1.3.0",
     "multiline": "1.0.2",
     "rimraf": "3.0.0",