add gitea ref tests

nixos-tests.nix

@@ -273,9 +273,19 @@ in
                   }
                 ) prJobNames
               );
+              rels = builtins.fromJSON (builtins.readFile releases);
+              relJobNames = builtins.attrNames rels;
+              relJobset = builtins.listToAttrs (
+                map (
+                  name: {
+                    inherit name;
+                    value = genDrv name;
+                  }
+                ) relJobNames
+              );
             in {
               trivial = genDrv "trivial";
-            } // prJobset
+            } // prJobset // relJobset
           '';
         in
         ''