The virtual hardware versions for VSphere 8.0 and 8.0U2 (hwversion 20 and 21) are missing in Foreman.

Was first reported on the forums here: https://community.theforeman.org/t/update-for-vmware-hardware-version/37242
According to the rbvmomi2 changelog, they should be already supported there: https://github.com/ManageIQ/rbvmomi2/blob/master/CHANGELOG.md