fix(package): update tar to version 6.0.0

Closes #333

Author: greenkeeper[bot]

package.json

@@ -86,7 +86,7 @@
     "s3": "^4.4.0",
     "socket.io": "^2.0.4",
     "stringify-object": "^3.2.1",
-    "tar": "^4.2.0",
+    "tar": "^6.0.0",
     "urldecode": "^1.0.1",
     "yargs": "^9.0.1"
   },