Support authenticated GitHub requests

```
thread 'main' panicked at src/main.rs:120:28:
Failed to find tag_name in response:
===
{"message":"API rate limit exceeded for 34.214.158.144. (But here's the good news: Authenticated requests get a higher rate limit. Check out the documentation for more details.)","documentation_url":"https://docs.github.com/rest/overview/resources-in-the-rest-api#rate-limiting"}

===
```

Start by inspecting src/main.rs around line 120 and tracing the GitHub request that produces the reported response. Read the linked GitHub rate-limiting documentation to understand the authentication requirements. Done means the CLI can make authenticated GitHub requests and no longer fails on the unauthenticated rate-limit response.

Written by the indexing model from the issue text.