Merge pull request #491 from ipfs/greenkeeper-bs58-4.0.0

Update bs58 to version 4.0.0 🚀

Author: daviddias

package.json

@@ -24,7 +24,7 @@
   "dependencies": {
     "async": "^2.1.4",
     "bl": "^1.1.2",
-    "bs58": "^3.1.0",
+    "bs58": "^4.0.0",
     "concat-stream": "^1.6.0",
     "detect-node": "^2.0.3",
     "flatmap": "0.0.3",