bugfixes:
  - proxmox - removed the forced conversion of non-string values to strings to be consistent with the module documentation (https://github.com/ansible-collections/community.general/pull/8646).
  - proxmox - fixed an issue where the new volume handling incorrectly converted ``null`` values into ``"None"`` strings (https://github.com/ansible-collections/community.general/pull/8646).
  - proxmox - fixed an issue where volume strings where overwritten instead of appended to in the new ``build_volume()`` method (https://github.com/ansible-collections/community.general/pull/8646).