chore: support ipv6 for server in docker

[aldo-airtm]

What type of PR is this?

• Bug Fix

Description

The listener address is hardcoded to IPv4-only (0.0.0.0) which breaks in an IPv6-only host. gunicorn supports the [::] host as a dualstack wildcard, so that's what I'm changing here.

How is this tested?

• Unit tests (pytest, jest)
• E2E Tests (Cypress)
• Manually
• N/A

Built the docker image locally and started it

[eradman]

Even without this change IPv6 appears to be reachable

$ nc -zv -4 sfdev2.lan 5001
Connection to sfdev2.lan (192.168.2.23) 5001 port [tcp/*] succeeded!
$ nc -zv -6 sfdev2.lan 5001
Connection to sfdev2.lan (fd00:52::17) 5001 port [tcp/*] succeeded!

What is the output of docker ps for you? (with and without this change)