Update environment variables for OpenVPN that start with generic `VPN_*` keyword since we are adding WireGuard support in https://github.com/openwisp/docker-openwisp/pull/226. Change `VPN_*` to `OPENVPN_*`.
Update environment variables for OpenVPN that start with generic
VPN_*keyword since we are adding WireGuard support in #226.Change
VPN_*toOPENVPN_*.