[Feature]: support IPv6 without `DHCP: "Y"`

[BPplays]

Is your proposal related to a problem?

based on other issues it seems IPv6 is only supported when using DHCP: "Y".
if you don't want to use a macvlan it doesn't seem possible to use IPv6; there are other programs like TibixDev‍/‍winboat that seem to be using the default mode, but even if you have your default docker network is setup to support IPv6 the windows container doesn't seem to get IPv6

Describe the solution you'd like.

i would like to see IPv6 support

Describe alternatives you've considered.

none

Additional context

No response

[kroese]

If you set:

environment:
  NETWORK: "user"

then IPv6 is available.