Include `mariadb-connector-c` (#307)

[shames0]

This makes it so that the caching_sha2_password plugin is included so connections to Mysql > 8.0 can succeed.

[shames0]

This intends to address: #307

[amacneil]

Can you explain what this is doing? I'm not familiar with mariadb-connector-c.

[shames0]

Yes, happy to hash out any questions or concerns here to make sure this is the right path forward.

But the intention with this change is to allow the docker run ... usage of dbmate (as documented in the README) compatible with MySQL 8 servers using the default/preferred Authentication plugin.

As outlined in #307 the dump action fails when run against a MySQL 8 server due to the missing caching_sha2_password plugin. I was able to find on the alpine package repository mariadb-connector-c which includes the needed caching_sha2_password.so library.

[amacneil]

Thanks for the extra info!