fix(package): update bencode to version 2.0.0

Author: greenkeeper[bot]

package.json

@@ -20,7 +20,7 @@
     "url": "https://github.com/webtorrent/bittorrent-tracker/issues"
   },
   "dependencies": {
-    "bencode": "^1.0.0",
+    "bencode": "^2.0.0",
     "bittorrent-peerid": "^1.0.2",
     "bn.js": "^4.4.0",
     "compact2string": "^1.2.0",