testing that conda works with this package

python is a core package: updating python in the root env (and getting a bad version) could potentially kill the whole conda system making a reinstall necessary. It would be nice if this package could include at least a test (outside of meta.yml, in the CI config directly) that conda itself works with this package: installing this package into the root env and installing an unrelated package and then downgrading `python` to an older version.