Breaking: bump leveldown and level-packager

Author: vweevers

package.json

@@ -15,8 +15,8 @@
   "browser": "browser.js",
   "dependencies": {
     "level-js": "^6.0.0",
-    "level-packager": "^5.1.0",
-    "leveldown": "^5.4.0"
+    "level-packager": "^6.0.0",
+    "leveldown": "^6.0.0"
   },
   "devDependencies": {
     "airtap": "^4.0.1",