fix(docs): 更新 docs/package.json 依赖版本

- 移除 yarn 依赖项，保持 vitepress-plugin-rss 依赖版本不变

Author: anghunk

docs/package.json

@@ -17,7 +17,6 @@
     "vite-plugin-vitepress-auto-sidebar": "^1.7.0",
     "vitepress-plugin-codeblocks-fold": "^1.2.27",
     "vitepress-plugin-comment-with-giscus": "^1.1.15",
-    "vitepress-plugin-rss": "^0.2.4",
-    "yarn": "^1.22.21"
+    "vitepress-plugin-rss": "^0.2.4"
   }
 }