removed unused dep

Author: pgte

package.json

@@ -60,7 +60,6 @@
     "ipfs-unixfs": "^0.1.11",
     "ipld-dag-pb": "^0.11.0",
     "ipld-resolver": "^0.11.1",
-    "is-ipfs": "^0.3.0",
     "left-pad": "^1.1.3",
     "lodash": "^4.17.4",
     "multihashes": "^0.4.5",