fix(package): update isomorphic-unfetch to version 3.0.0

Closes #8

Author: greenkeeper[bot]

package.json

@@ -9,7 +9,7 @@
   "author": "github.com/cernadasjuan",
   "license": "MIT",
   "dependencies": {
-    "isomorphic-unfetch": "2.0.0",
+    "isomorphic-unfetch": "3.0.0",
     "next": "4.2.1",
     "react": "16.2.0",
     "react-bootstrap": "0.31.5",