feat(document_ai-v1beta3): Expose model_type field in processor versi…

…on APIs (#24746)

google-cloud-document_ai-v1beta3/proto_docs/google/cloud/documentai/v1beta3/processor.rb

@@ -57,6 +57,9 @@ module V1beta3
         # @!attribute [rw] deprecation_info
         #   @return [::Google::Cloud::DocumentAI::V1beta3::ProcessorVersion::DeprecationInfo]
         #     If set, information about the eventual deprecation of this version.
+        # @!attribute [r] model_type
+        #   @return [::Google::Cloud::DocumentAI::V1beta3::ProcessorVersion::ModelType]
+        #     Output only. The model type of this processor version.
         class ProcessorVersion
           include ::Google::Protobuf::MessageExts
           extend ::Google::Protobuf::MessageExts::ClassMethods
@@ -102,6 +105,18 @@ module State
             # The processor version is being imported.
             IMPORTING = 8
           end
+
+          # The possible model types of the processor version.
+          module ModelType
+            # The processor version has unspecified model type.
+            MODEL_TYPE_UNSPECIFIED = 0
+
+            # The processor version has generative model type.
+            MODEL_TYPE_GENERATIVE = 1
+
+            # The processor version has custom model type.
+            MODEL_TYPE_CUSTOM = 2
+          end
         end
 
         # Contains the alias and the aliased resource name of processor version.