bump-formula-pr: fix forking logic
bump-formula-pr: fix forking logic

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