IPv6 subnet format not accepted

[kroese]

Describe the issue

When I want to allow any IPv6 address I use:

environment:
      - "SMTP_NETWORKS=0.0.0.0/0,[::]/0"

Expected behavior

I expect this to be correct, I also tried it as ::/0 but in both cases I get:

[::]/0 is not in proper IPv4 or IPv6 subnet format. Ignoring.

Other subnets that do not work:

[fe80::]/10 is not in proper IPv4 or IPv6 subnet format. Ignoring.
[fd87::]/10 is not in proper IPv4 or IPv6 subnet format. Ignoring.
[::1]/128 is not in proper IPv4 or IPv6 subnet format. Ignoring.

This has something to do with the regex being performed. Is there any workaround or can this bug be solved?