message: Fix a bug that SOK cannot be compiled in TF2.8
diff: #include "parameters/param_interface.h"
  #include "tensorflow/core/framework/resource_var.h"
  +// For TF2.8: resource_mgr.h was removed from resource_var.h in TF2.8, so it needs to
  +// be added manually.
  +#include "tensorflow/core/framework/resource_mgr.h"
  +
  namespace tensorflow {
  class EmbeddingVariable : public ResourceBase {
  