Bump mysql-connector-java from 8.0.26 to 8.0.28

Bumps [mysql-connector-java](https://github.com/mysql/mysql-connector-j) from 8.0.26 to 8.0.28.
- [Release notes](https://github.com/mysql/mysql-connector-j/releases)
- [Changelog](https://github.com/mysql/mysql-connector-j/blob/release/8.0/CHANGES)
- [Commits](https://github.com/mysql/mysql-connector-j/commits)

---
updated-dependencies:
- dependency-name: mysql:mysql-connector-java
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

build.gradle

@@ -61,7 +61,7 @@ ext {
         "dm"                         : fileTree(dir: 'libs', includes: ["jdbcDriver-18.jar"]),
         "kingbase"                   : fileTree(dir: 'libs', includes: ["kingbase8-8.2.0.jar"]),
         "h2"                         : "com.h2database:h2:2.1.210",
-        "mysql"                      : "mysql:mysql-connector-java:8.0.26",
+        "mysql"                      : "mysql:mysql-connector-java:8.0.28",
         "sqlite"                     : "org.xerial:sqlite-jdbc:3.36.0.3",
         "firebird"                   : "org.firebirdsql.jdbc:jaybird:4.0.5.java8",
         //cache