bump version to v2.12.0-dev
bump version to v2.12.0-dev

jrassa/EmulationStation,joolswills/EmulationStation,joolswills/EmulationStation,jrassa/EmulationStation,joolswills/EmulationStation,jrassa/EmulationStation,jrassa/EmulationStation,joolswills/EmulationStation