chore: rename flags (#200)

proto/greptime/v1/ddl.proto

@@ -108,7 +108,7 @@ message AlterExpr {
     AddColumns add_columns = 4;
     DropColumns drop_columns = 5;
     RenameTable rename_table = 6;
-    ChangeColumnTypes change_column_types = 7;
+    ModifyColumnTypes modify_column_types = 7;
     ChangeTableOptions change_table_options = 8;
     ChangeColumnFulltext change_column_fulltext = 9;
   }
@@ -146,7 +146,7 @@ message AddColumns { repeated AddColumn add_columns = 1; }
 
 message DropColumns { repeated DropColumn drop_columns = 1; }
 
-message ChangeColumnTypes { repeated ChangeColumnType change_column_types = 1; }
+message ModifyColumnTypes { repeated ModifyColumnType modify_column_types = 1; }
 
 message RenameTable { string new_table_name = 1; }
 
@@ -155,7 +155,7 @@ message AddColumn {
   AddColumnLocation location = 3;
 }
 
-message ChangeColumnType {
+message ModifyColumnType {
   string column_name = 1;
   ColumnDataType target_type = 2;
   ColumnDataTypeExtension target_type_extension = 3;