Setup cron job to download and test mayavi available on PyPI

The Traits GitHub Actions CI workflow - https://github.com/enthought/traits/blob/2dcf65198ca9c3cd4a2f3e00523ab0e20efe076e/.github/workflows/test-from-pypi.yml - downloads, installs the latest version of Traits available on PyPI and runs the testsuite. We should be doing the same for MayaVi. Such a job might be especially useful for MayaVi, given the larger/wider adoption of MayaVi and the regular issues that we have observed related to PyPI installs.