URL in description and README broken

The URL in the repository description and the one in the 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-ETyree60/

更新 README 和仓库描述中的 URL，将 githubschool 的副本链接替换为 https://githubschool.github.io/github-games-ETyree60/。验证这两个位置都指向该仓库自己的游戏页面，并确认 issue 中的两个失效链接已解决。

由索引模型根据 Issue 内容生成。