[DOC][MINOR] Update starrocks.md (#4304)

Author: zml1206

docs/content.zh/docs/connectors/pipeline-connectors/starrocks.md

@@ -240,7 +240,7 @@ pipeline:
     自动设置分桶数量</a>。对于 StarRocks 2.5 之前的版本必须设置，否则无法自动创建表。
 
 * 对于表结构变更同步
-  * 只支持增删列
+  * 支持创建/删除/清空表，增加/删除/重命名列，修改列类型
   * 新增列只能添加到最后一列
   * 如果使用 StarRocks 3.2 及之后版本，并且通过连接器来自动建表, 可以通过配置 `table.create.properties.fast_schema_evolution` 为 `true`
     来加速 StarRocks 执行变更。

docs/content/docs/connectors/pipeline-connectors/starrocks.md

@@ -248,7 +248,7 @@ pipeline:
     otherwise you must set the option.
 
 * For schema change synchronization
-  * only supports add/drop columns
+  * supports create/drop/truncate table, add/drop/rename columns and alter column types
   * the new column will always be added to the last position
   * if your StarRocks version is 3.2 or later, and using the connector to create table automatically,
     you can set `table.create.properties.fast_schema_evolution` to `true` to speed up the schema change.