chore(package): update espree to version 3.3.1 (#394)

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -42,7 +42,7 @@
     "eslint-config-babel": "^1.0.1",
     "eslint-plugin-babel": "^3.3.0",
     "eslint-plugin-flow-vars": "^0.5.0",
-    "espree": "^3.0.0",
+    "espree": "^3.3.1",
     "mocha": "^3.0.0"
   }
 }