Upgrade java-mysql-connector to support new server authentication

MySQL servers 8.0+ have changed their default authentication, and clients < 5.7 won't be able to connect to them without extra effort. The version supplied with Grouper is 5.1.45.

(So nobody has set up an 8.0 database with Grouper yet??)

https://dev.mysql.com/doc/refman/5.7/en/caching-sha2-pluggable-authentication.html

In MySQL 5.7, the default authentication plugin is mysql_native_password. As of MySQL 8.0, the default authentication plugin is changed to caching_sha2_password. To enable MySQL 5.7 clients to connect to 8.0 and higher servers using accounts that authenticate with caching_sha2_password, the MySQL 5.7 client library and client programs support the caching_sha2_password client-side authentication plugin. This improves MySQL 5.7 client connect-capability compatibility with respect to MySQL 8.0 and higher servers, despite the differences in default authentication plugin.

So we should test whether a 5.x will work fine in Grouper to connect with an 8.x database, or whether we would need to upgrade the mysql connector to 8.x.