fix(flake): switch to github ref

Switch from a flake ref to a github ref as renovate cannot resolve flake
refs, and they are slightly impure.

flake-modules/tests.nix

@@ -6,7 +6,6 @@
       checks =
         let
           testDomain = "webnstest.example";
-          dynamicZonesDir = "/var/lib/named/zones";
           zoneFile = pkgs.writeText "${testDomain}.zoneinfo" ''
             $ORIGIN .
             $TTL 60 ; 1 minute
@@ -27,7 +26,14 @@
             nsupdate                  IN  AAAA  ::1
           '';
 
-          webnsupdate-machine = {
+          webnsupdate-machine =
+            { config, ... }:
+            let
+              bindCfg = config.services.bind;
+              bindData = bindCfg.directory;
+              dynamicZonesDir = "${bindData}/zones";
+            in
+            {
               imports = [ self.nixosModules.webnsupdate ];
 
               config = {
@@ -71,9 +77,8 @@
                   # shellcheck disable=SC2211,SC1127
                   rm -f ${dynamicZonesDir}/* # reset dynamic zones
 
-                ${pkgs.coreutils}/bin/mkdir -m 0755 -p ${dynamicZonesDir}
+                  mkdir -m 0755 -p ${dynamicZonesDir}
-                chown "named" ${dynamicZonesDir}
+                  chown named ${dynamicZonesDir}
-                chown "named" /var/lib/named
 
                   # copy dynamic zone's file to the dynamic zones dir
                   cp ${zoneFile} ${dynamicZonesDir}/${testDomain}
@@ -87,6 +92,7 @@
             nodes.machine = webnsupdate-machine;
             testScript = ''
               machine.start(allow_reboot=True)
+              machine.wait_for_unit("bind.service")
               machine.wait_for_unit("webnsupdate.service")
 
               # ensure base DNS records area available