gh-stack is impossible to install: API rate limit exceeded

```
% gh extension install github/gh-stack
could not check for binary extension: HTTP 403: API rate limit exceeded for A.B.C.D. (But here's the good news: Authenticated requests get a higher rate limit. Check out the documentation for more details.) (https://api.github.com/repos/github/gh-stack/releases/latest)
```

首先重现 `gh extension install github/gh-stack`，并检查请求 `https://api.github.com/repos/github/gh-stack/releases/latest` 的安装路径。使用未经身份验证的请求确认失败模式，并定义预期行为；完成的标准是能够在不出现此速率限制失败的情况下安装扩展。

由索引模型根据 Issue 内容生成。