cmd/update.sh: update Git logic.
cmd/update.sh: update Git logic.

Co-authored-by: Maxim Belkin <032baa6ccf1d4eaa4536fc4f9b83b9a1f593449a@gmail.com>
vitorgalvao/brew,sjackman/homebrew,sjackman/homebrew,MikeMcQuaid/brew,EricFromCanada/brew,nandub/brew,nandub/brew,MikeMcQuaid/brew,claui/brew,MikeMcQuaid/brew,JCount/brew,EricFromCanada/brew,vitorgalvao/brew,Homebrew/brew,konqui/brew,konqui/brew,claui/brew,EricFromCanada/brew,Homebrew/brew,konqui/brew,sjackman/homebrew,JCount/brew,EricFromCanada/brew,claui/brew,nandub/brew,JCount/brew,vitorgalvao/brew,MikeMcQuaid/brew,Homebrew/brew,vitorgalvao/brew,nandub/brew,JCount/brew,sjackman/homebrew,Homebrew/brew,claui/brew,konqui/brew