Update .travis.yml to use a newer version of cmake
Update .travis.yml to use a newer version of cmake

ColinKinloch/gfx,davll/gfx,tanderegg/gfx,tanderegg/gfx,JohnColanduoni/gfx,Bastacyclop/gfx,JohnColanduoni/gfx,gfx-rs/gfx-rs,ColinKinloch/gfx,sectopod/gfx-rs