fix(package): update @robotlegsjs/core to version 2.0.0

Author: greenkeeper[bot]

package.json

@@ -73,7 +73,7 @@
     "lib": "./lib"
   },
   "dependencies": {
-    "@robotlegsjs/core": "^1.0.3",
+    "@robotlegsjs/core": "^2.0.0",
     "@robotlegsjs/signals": "^1.1.0",
     "tslib": "^1.11.1"
   },