no need to change go.mod when update go toolchain

[lijie0123]

Bug Report

1. What did you do?
   compile tidb-tools with go 1.19
   
   the go directive in go.mod means minimal version ，it can just keep even we use higher go toolchain

2. What did you expect to see?
   It can compile

3. What did you see instead?
   It can not compile

4. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?

5. which tool are you using?

6. what versionof tool are you using (pump -V or tidb-lightning -V or syncer -V)?