Bump leveldown to prevent dedupe

Author: vweevers

package.json

@@ -17,7 +17,7 @@
   "dependencies": {
     "level-js": "^5.0.0",
     "level-packager": "^5.1.0",
-    "leveldown": "^5.3.0",
+    "leveldown": "^5.4.0",
     "opencollective-postinstall": "^2.0.0"
   },
   "devDependencies": {