fix(package): update fastify-helmet to version 2.1.0

Closes #12

Author: greenkeeper[bot]

package.json

@@ -24,7 +24,7 @@
   "homepage": "https://github.com/crudjs/rest-fastify-rethinkdb#readme",
   "dependencies": {
     "fastify": "^0.30.2",
-    "fastify-helmet": "^1.0.1",
+    "fastify-helmet": "^2.1.0",
     "moment": "^2.19.1",
     "rethinkdbdash": "^2.3.31",
     "slug": "^0.9.1"