feat: add model_type in v1beta3 processor proto

PiperOrigin-RevId: 603726122

google/cloud/documentai/v1beta3/processor.proto

@@ -82,6 +82,18 @@ message ProcessorVersion {
     IMPORTING = 8;
   }
 
+  // The possible model types of the processor version.
+  enum 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;
+  }
+
   // The resource name of the processor version.
   // Format:
   // `projects/{project}/locations/{location}/processors/{processor}/processorVersions/{processor_version}`
@@ -113,6 +125,9 @@ message ProcessorVersion {
 
   // If set, information about the eventual deprecation of this version.
   DeprecationInfo deprecation_info = 13;
+
+  // Output only. The model type of this processor version.
+  ModelType model_type = 15 [(google.api.field_behavior) = OUTPUT_ONLY];
 }
 
 // Contains the alias and the aliased resource name of processor version.