chore(package): update assume to version 2.0.1

Closes #18

Author: greenkeeper[bot]

package.json

@@ -35,7 +35,7 @@
     "react-dom": "^15.4.0"
   },
   "devDependencies": {
-    "assume": "~1.5.0",
+    "assume": "~2.0.1",
     "istanbul": "~0.4.5",
     "mocha": "~3.1.2",
     "pre-commit": "~1.2.0"