There's a closed pull request on the void-packages repository

Networkmanager 1.20.8
https://github.com/void-linux/void-packages/pull/13560

Description:
I opened this PR to prevent people from wasting time in updating this package.

NetworkManager removed support for their legacy API, which causes NetworkManager-vpnc and NetworkManager-openvpn to break. We should delay this update until upstream has fixed this issue.