Bump testing deps (#67)

Author: tclindner

package.json

@@ -50,9 +50,9 @@
     "eslint-config-tc": "^2.3.0",
     "eslint-formatter-pretty": "^1.3.0",
     "figures": "^2.0.0",
-    "mocha": "^3.5.0",
-    "nyc": "^11.1.0",
-    "sinon": "^3.2.1"
+    "mocha": "^4.0.1",
+    "nyc": "^11.4.1",
+    "sinon": "^4.1.3"
   },
   "engines": {
     "node": ">=4.2.0",