Upgrade command #2673

There is no gh upgrade sub-command, but the path depends on your package manager:\n\n- Homebrew: brew upgrade gh\n- Windows winget: winget upgrade GitHub.cli\n- Windows scoop: scoop update gh\n- Linux apt: curl -fsSL https://cli.github.com/packages/githubcli-archive-keyring.gpg | sudo dd of=/usr/share/keyrings/githubcli-archive-keyring.gpg && echo 'deb [arch=amd64 signed-by=/usr/share/keyrings/githubcli-archive-keyring.gpg] https://cli.github.com/packages stable main' | sudo tee /etc/apt/sources.list.d/github-cli.list && sudo apt update && sudo apt install gh\n- Linux snap: snap refresh gh\n\nRun which gh or Get-Command gh to figure out which method you used.