Bump r2dbc-mariadb from 0.8.3-beta1 to 0.8.4-rc in /modules/mariadb (#3300)
Bump r2dbc-mariadb from 0.8.3-beta1 to 0.8.4-rc in /modules/mariadb (#3300)

Bumps [r2dbc-mariadb](https://github.com/mariadb-corporation/mariadb-connector-r2dbc) from 0.8.3-beta1 to 0.8.4-rc.
- [Release notes](https://github.com/mariadb-corporation/mariadb-connector-r2dbc/releases)
- [Changelog](https://github.com/mariadb-corporation/mariadb-connector-r2dbc/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mariadb-corporation/mariadb-connector-r2dbc/commits)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>

Co-authored-by: dependabot[bot] <1c358da00a777d4e9898c1280ab801e2df165188@users.noreply.github.com>
testcontainers/testcontainers-java,testcontainers/testcontainers-java,testcontainers/testcontainers-java,rnorth/test-containers,rnorth/test-containers,rnorth/test-containers