IPv6 support

[sparrovv]

Driver version

2.1.2

Redshift version

PostgreSQL 8.0.2 on i686-pc-linux-gnu, compiled by GCC gcc (GCC) 3.4.2 20041017 (Red Hat 3.4.2-6.fc3), Redshift 1.0.70634

Client Operating System

macos

Python version

3.9

Problem description

At my company we started using VPN that only works over IPv6.
Since that we started seeing below errors when connecting:

 08:57:16 Encountered an error: Database Error ('communication error', gaierror(8, 'nodename nor servname provided, or not known'))

I looked into the code and it seems that the driver only works over ipv4.
I started a draft PR: #229
But I'm not sure whether that's enough.

Other SQL clients works fine over IPv6 (datagrip)

[Brooke-white]

Hi @sparrovv , thank you for raising this issue and corresponding draft PR. I will raise this issue with the team for discussion and share our next steps here.