bump-formula-pr: use default remote if forcing Homebrew on Linux
bump-formula-pr: use default remote if forcing Homebrew on Linux

JCount/brew,MikeMcQuaid/brew,nandub/brew,Homebrew/brew,EricFromCanada/brew,Homebrew/brew,JCount/brew,nandub/brew,MikeMcQuaid/brew,Homebrew/brew,MikeMcQuaid/brew,JCount/brew,EricFromCanada/brew,nandub/brew,EricFromCanada/brew,nandub/brew,Homebrew/brew,EricFromCanada/brew,JCount/brew,MikeMcQuaid/brew