chore(package): update lerna to version 3.18.4

Closes #81

Author: greenkeeper[bot]

package.json

@@ -44,7 +44,7 @@
   },
   "devDependencies": {
     "husky": "^0.13.1",
-    "lerna": "2.0.0-beta.36",
+    "lerna": "3.18.4",
     "standard": "^8.3.0"
   }
 }