datahub: Update pygame version
datahub: Update pygame version

1.9.3 doesn't have Python 3.7 wheels, but 1.9.6 does

berkeley-dsep-infra/datahub,ryanlovett/datahub,berkeley-dsep-infra/datahub,berkeley-dsep-infra/datahub,ryanlovett/datahub,ryanlovett/datahub