Add bfx-api-node-models as a dependency

Change bfx-api-node-models  as a dependency instead of a devDependency 
as its actually being used on code

package.json

@@ -38,7 +38,6 @@
   "homepage": "http://bitfinexcom.github.io/bfx-api-node-util/",
   "devDependencies": {
     "babel-eslint": "^10.0.3",
-    "bfx-api-node-models": "^1.1.0",
     "chai": "^4.2.0",
     "mocha": "^6.2.0",
     "standard": "^14.1.0"
@@ -47,6 +46,7 @@
     "babel-plugin-transform-object-rest-spread": "^6.26.0",
     "babel-plugin-transform-regenerator": "^6.26.0",
     "babel-preset-env": "^1.7.0",
+    "bfx-api-node-models": "^1.1.0",
     "bignumber.js": "^6.0.0",
     "copy": "^0.3.2"
   }