github_api: fix PAT URL

[gromgit]

Ensure that recommended URL matches "scopes required" list. Closes #13030.

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[BrewTestBot]

Review period will end on 2022-03-25 at 02:23:13 UTC.

[Bo98]

Do you have a repo that reproduces this? Feels like something that would only happen to private repositories.

[gromgit]

Aside from #13030, it happened to me back when (I think) GitHub changed their PAT format. My old Homebrew PAT also had just public_repo scope rather than the overarching repo, and I got the same error after using the regenerated PAT. I eventually had to create a new PAT, but forgot to file a PR to fix this.

And I definitely don't deal with private repos.

[MikeMcQuaid]

Thanks again @gromgit!

[BrewTestBot]

Review period skipped due to critical label.

[gromgit]

@namnn89, note the following:

1. Please post text output as text, not screenshots. Screen captures are particularly hard to read on mobile platforms.
2. Your connection to GitHub seems to be failing before the full Homebrew contents can be downloaded. Please read Unable to install: "fatal: the remote end hung up unexpectedly" discussions#666 and see if any of the recommendations there work for you. If not, you should follow up there, not here on a closed PR.