Bump mysql-connector-java from 6.0.3 to 8.0.28 in /core

Bumps [mysql-connector-java](https://github.com/mysql/mysql-connector-j) from 6.0.3 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/compare/6.0.3...8.0.28)

---
updated-dependencies:
- dependency-name: mysql:mysql-connector-java
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/core/pom.xml b/core/pom.xml
index b7ab26f..f3ac661 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -216,7 +216,7 @@
       <dependency>
         <groupId>mysql</groupId>
         <artifactId>mysql-connector-java</artifactId>
-        <version>6.0.3</version>
+        <version>8.0.28</version>
       </dependency>
       <dependency>
         <groupId>net.sourceforge.nekohtml</groupId>