nixos/release: make ipv6 tests as important as legacy IP tests

IPv6 container support broke a while ago and we didn't notice it. Making
them part of the (small) release test set should fix that. At this point
in time they should be granted the same amount of importance as the
legacy IP tests.

nixos/release-combined.nix

@@ -64,6 +64,7 @@ in rec {
         #(all nixos.tests.containers)
         (all nixos.tests.containers-imperative)
         (all nixos.tests.containers-ipv4)
+        (all nixos.tests.containers-ipv6)
         nixos.tests.chromium.x86_64-linux or []
         (all nixos.tests.firefox)
         (all nixos.tests.firewall)

nixos/release-small.nix

@@ -33,6 +33,7 @@ in rec {
       inherit (nixos'.tests)
         containers-imperative
         containers-ipv4
+        containers-ipv6
         firewall
         ipv6
         login