Updating mocha version to address a security fix in one of its dependencies

Author: jlcvp

package.json

@@ -28,13 +28,13 @@
   },
   "homepage": "https://github.com/jlcvp/fcm-node",
   "dependencies": {
-    "firebase-admin": "^4.1.3",
-    "mocha": "^3.2.0",
+    "firebase-admin": "^4.2.1",
+    "mocha": "^4.0.1",
     "retry": "^0.9.0"
   },
   "scripts": {
-    "test": "mocha",
-    "debugtest": "mocha --debug-brk $npm_package_options_mocha"
+    "test": "mocha --exit",
+    "debugtest": "mocha --debug-brk $npm_package_options_mocha --exit"
   },
   "directories": {
     "test": "test"