Auth via username and password is now obsolete

[curquiza]

Since GitHub stopped maintaining basic auth via username and password:

Note: GitHub has discontinued password authentication to the API starting on November 13, 2020 for all GitHub.com accounts, including those on a GitHub Free, GitHub Pro, GitHub Team, or GitHub Enterprise Cloud plan. You must now authenticate to the GitHub API with an API token, such as an OAuth access token, GitHub App installation access token, or personal access token, depending on what you need to do with the token. For more information, see "Troubleshooting."

Ref: https://docs.github.com/en/free-pro-team@latest/rest/overview/other-authentication-methods#via-username-and-password

Should this package keep maintaining authentication via username and password? Shouldn't the main way to authenticate be via PAT?

I would be happy to do a PR 🙂

[curquiza]

Since we can pass the PAT in password

client = Octokit::Client.new(:login => 'curquiza', :password => 'github_pat')

I'm not sure doing changes in the code would be useful changes, plus they would be breaking.

But I still can open a PR to make the README more up-to-date.

[curquiza]

I opened #1314
Feel free to refuse or request any changes.