Update procedure to configure git

[ymmt2005]

The current procedure for configuring git does not allow it to push commits
besides the current repository, even if the app token may have access to other
repositories. It also does not allow git to clone such a repository.

This new procedure configures gh first and then calls gh auth setup-git
to configure git so it will work for any repository that the token has access to.

[Copilot]

Pull Request Overview

This PR updates the git configuration procedure to properly enable pushing commits by configuring gh first and using gh auth setup-git instead of manually setting git user credentials. The changes address the issue where the previous procedure configured git but didn't allow actual push operations.

• Simplifies the configuration process by leveraging gh auth setup-git instead of manual git config commands
• Moves the tip about finding bot user IDs to appear before the configuration section for better readability
• Updates the procedure title to reflect that it now configures both gh and git CLI tools

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[ymmt2005]

It seems #273 and #285 try to solve the same issue with a different approach.
Though I'm unsure which one will be the best, I hope at least one of them will be merged.