workflows/tests: fix gem caching
workflows/tests: fix gem caching

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