fix(package): update lru-cache to version 5.1.0

Closes #15

Author: greenkeeper[bot]

package.json

@@ -41,7 +41,7 @@
     "prettier": "^1.5.3"
   },
   "dependencies": {
-    "lru-cache": "^4.1.1",
+    "lru-cache": "^5.1.0",
     "object-hash": "^1.1.8"
   }
 }