Bump deferred-leveldown

Author: vweevers

package.json

@@ -25,7 +25,7 @@
   ],
   "dependencies": {
     "catering": "^2.0.0",
-    "deferred-leveldown": "~5.3.0",
+    "deferred-leveldown": "^6.0.0",
     "level-errors": "^3.0.0",
     "level-iterator-stream": "^5.0.0",
     "level-supports": "^2.0.0",