feat: Add Presto dialect to bigquerymigration v2 client library

PiperOrigin-RevId: 460797158

google/cloud/bigquery/migration/v2/migration_entities.proto

@@ -135,7 +135,7 @@ message MigrationTask {
   // Translation_Oracle2BQ, Translation_HiveQL2BQ, Translation_SparkSQL2BQ,
   // Translation_Snowflake2BQ, Translation_Netezza2BQ,
   // Translation_AzureSynapse2BQ, Translation_Vertica2BQ,
-  // Translation_SQLServer2BQ.
+  // Translation_SQLServer2BQ, Translation_Presto2BQ.
   string type = 2;
 
   // Output only. The current state of the task.

google/cloud/bigquery/migration/v2/translation_config.proto

@@ -91,6 +91,12 @@ message Dialect {
 
     // The SQL Server dialect
     SQLServerDialect sql_server_dialect = 11;
+
+    // The Postgresql dialect
+    PostgresqlDialect postgresql_dialect = 12;
+
+    // The Presto dialect
+    PrestoDialect presto_dialect = 13;
   }
 }
 
@@ -142,6 +148,12 @@ message VerticaDialect {}
 // The dialect definition for SQL Server.
 message SQLServerDialect {}
 
+// The dialect definition for Postgresql.
+message PostgresqlDialect {}
+
+// The dialect definition for Presto.
+message PrestoDialect {}
+
 // Represents a map of name mappings using a list of key:value proto messages of
 // existing name to desired output name.
 message ObjectNameMappingList {