formulae: fix sed extended regex flag on macOS.
formulae: fix sed extended regex flag on macOS.

Closes #9367
Fixes #9388

EricFromCanada/brew,nandub/brew,nandub/brew,sjackman/homebrew,claui/brew,sjackman/homebrew,Homebrew/brew,sjackman/homebrew,vitorgalvao/brew,konqui/brew,nandub/brew,Homebrew/brew,MikeMcQuaid/brew,konqui/brew,EricFromCanada/brew,claui/brew,JCount/brew,Homebrew/brew,sjackman/homebrew,JCount/brew,vitorgalvao/brew,claui/brew,EricFromCanada/brew,EricFromCanada/brew,konqui/brew,claui/brew,vitorgalvao/brew,MikeMcQuaid/brew,konqui/brew,JCount/brew,MikeMcQuaid/brew,MikeMcQuaid/brew,JCount/brew,vitorgalvao/brew,Homebrew/brew,nandub/brew