URL in description and README broken

The URL in the repository description and README are pointing to githubschool's copy of the game instead of yours.

Please fix both so they point to your copy of the game at https://githubschool.github.io/github-games-acg2dkq

更新 README 中的 URL 和仓库描述，使其指向 https://githubschool.github.io/github-games-acg2dkq。验证两个链接都能解析到此仓库的游戏页面，并且不再保留任何对 githubschool 副本的引用。

由索引模型根据 Issue 内容生成。