Startup crash with Redix 1.2.2 using `:inet6` in socket opts

[simoncocking]

We run our application at Fly.io, and so all our networking is IPv6. As such we do (something like) the following:

{:ok, conn} = Redix.start_link(redix_url, name: :my_redix, socket_opts: [:inet6], sync_connect: true)

After upgrading to Redix 1.2.2 and with the introduction of NimbleOptions, Redix now fails to start with the following error:

%NimbleOptions.ValidationError{
  message: "invalid value for :socket_opts option: expected keyword list, got: [:inet6]",
  key: :socket_opts,
  value: [:inet6],
  keys_path: []
}

Are we holding it wrong? Is there another way to specify IPv6 that NimbleOptions won't complain about?

[Xetera]

The ipv6 option doesn't work for me with the same error even with version 1.0