dev-python/pymountboot: add python 3.10
commit 139e89b26e15e256aece2096b0e316ca37bc01c4 Author: Miezhiko <Miezhiko@gmail.com> Date: Tue Jan 18 16:20:53 2022 +0400 dev-python/pymountboot: py3.10 support Package-Manager: Portage-3.0.30, Repoman-3.0.3 Signed-off-by: Miezhiko <Miezhiko@gmail.com> Signed-off-by: Michał Górny <mgorny@gentoo.org>