feat: add hexo-theme-butterfly (#284)

[skip ci]

A Hexo Theme: Butterfly

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **New Features**
- Added support for the `hexo-theme-butterfly` package, allowing users
to utilize any version of this theme in their projects.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

package.json

@@ -252,6 +252,9 @@
     "@pubinfo"
   ],
   "allowPackages": {
+    "hexo-theme-butterfly": {
+      "version": "*"
+    },
     "pixpro": {
       "version": "*"
     },