Merge pull request #127 from ethereumjs/update-hdkey-dependency

Updated hdkey dependency from v1.1.1 to v2.0.1

Author: ryanio

Diff for: package.json

@@ -46,7 +46,7 @@
     "aes-js": "^3.1.1",
     "bs58check": "^2.1.2",
     "ethereumjs-util": "^7.0.2",
-    "hdkey": "^1.1.1",
+    "hdkey": "^2.0.1",
     "randombytes": "^2.0.6",
     "scrypt-js": "^3.0.1",
     "utf8": "^3.0.0",