Make libmariadb-dev-compat also Breaks+Replaces old libmariadbclient-dev

Fixes the following error:
  dpkg: error processing archive libmariadb-dev-compat_10.3.12-2_amd64.deb
  (--unpack):
    trying to overwrite '/usr/bin/mysql_config', which is also in package
    libmariadbclient-dev 1:10.1.37-3

Complements commit dbb4099a
Needs to be versioned because of 74733c68