Remove brog from homebrew

[iwittkau]

Hi,

I'm filing this issue to communicate that borg is about to get removed from homebrew. I filed a pull request there to remove the borg formula:

Homebrew/homebrew-core#47808

The borg formula blocks upgrading the go formula and is holding back important security fixes.

The underlying reason for this seems to be that the borg formula is outdated and the tests fail permanently because of ok-borg.org being down. Also the formula uses deprecated fields which makes it hard to fix for non-borg developers.