Skip mixed version when 2 nodes

Author: MarcialRosales

deps/rabbitmq_auth_backend_cache/test/rabbit_auth_clear_cache_command_SUITE.erl

@@ -47,7 +47,10 @@ end_per_suite(Config) ->
     rabbit_ct_helpers:run_teardown_steps(Config).
 
 init_per_group(cluster_size_2, Config) ->
-    init_per_multinode_group(cluster_size_2, Config, 2);
+    case rabbit_ct_helpers:is_mixed_versions() of 
+        true -> {skip, "cluster size 2 isn't mixed versions compatible"};
+        false -> init_per_multinode_group(cluster_size_2, Config, 2)
+    end;
 init_per_group(Group, Config) ->
     init_per_multinode_group(Group, Config, 1).