fix(package): update lodash to version 4.17.15

Closes #58

Author: greenkeeper[bot]

package.json

@@ -35,7 +35,7 @@
     "async": "2.6.1",
     "debug": "4.1.0",
     "joi": "14.0.4",
-    "lodash": "4.17.11",
+    "lodash": "4.17.15",
     "semver": "5.6.0",
     "sequelize": "4.41.1"
   },