Upgrade to atom-package-manager@0.89

apm/package.json

@@ -6,6 +6,6 @@
     "url": "https://github.com/atom/atom.git"
   },
   "dependencies": {
-    "atom-package-manager": "0.88.0"
+    "atom-package-manager": "0.89.0"
   }
 }