Bump com.mysql:mysql-connector-j from 8.4.0 to 9.1.0 in /Plan

Bumps [com.mysql:mysql-connector-j](https://github.com/mysql/mysql-connector-j) from 8.4.0 to 9.1.0.
- [Changelog](https://github.com/mysql/mysql-connector-j/blob/release/9.x/CHANGES)
- [Commits](mysql/mysql-connector-j@8.4.0...9.1.0)

---
updated-dependencies:
- dependency-name: com.mysql:mysql-connector-j
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Plan/build.gradle

@@ -89,7 +89,7 @@ subprojects {
         caffeineVersion = "3.1.8"
         jettyVersion = "11.0.24"
         caffeineVersion = "2.9.2"
-        mysqlVersion = "8.4.0"
+        mysqlVersion = "9.1.0"
         mariadbVersion = "3.5.1"
         sqliteVersion = "3.47.1.0"
         adventureVersion = "4.17.0"