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-islaso/

更新 README 中的 URL 和仓库描述，使两者都指向 https://githubschool.github.io/github-games-islaso/。验证每个位置现在都使用所要求的游戏副本 URL，并且不再保留旧的 githubschool 副本链接。

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