Fix broken link to Connector/J docs (#15433) (#15442)

develop/dev-guide-sample-application-java-jdbc.md

@@ -291,7 +291,7 @@ Unless you need to write complex SQL statements, it is recommended to use [ORM](
 
 ## Next steps
 
-- Learn more usage of MySQL Connector/J from [the documentation of MySQL Connector/J](https://dev.mysql.com/doc/connector-j/8.1/en/).
+- Learn more usage of MySQL Connector/J from [the documentation of MySQL Connector/J](https://dev.mysql.com/doc/connector-j/en/).
 - Learn the best practices for TiDB application development with the chapters in the [Developer guide](/develop/dev-guide-overview.md), such as [Insert data](/develop/dev-guide-insert-data.md), [Update data](/develop/dev-guide-update-data.md), [Delete data](/develop/dev-guide-delete-data.md), [Single table reading](/develop/dev-guide-get-data-from-single-table.md), [Transactions](/develop/dev-guide-transaction-overview.md), and [SQL performance optimization](/develop/dev-guide-optimize-sql-overview.md).
 - Learn through the professional [TiDB developer courses](https://www.pingcap.com/education/) and earn [TiDB certifications](https://www.pingcap.com/education/certification/) after passing the exam.
 - Learn through the course for Java developers: [Working with TiDB from Java](https://eng.edu.pingcap.com/catalog/info/id:212).