outdated: allow forcing verbose output

Closes #27813.
Add official `gh` formula

The formula is from https://github.com/jingweno/homebrew-gh
Use single quote everywhere
Remove caveats section
Inline SHAs
Remove bottle content for now
More robust test of correct installation of `gh`

Also inline VERSION
No autoupdate for script/make
Bump gh to 2.1.0
Use tarball for gh
gh: update 2.1.0 bottle.