fix: update `lol_dba` gem

There was an exception raised when a model contained enums caused by double loading of models (see [lol_dba#39](https://github.com/plentz/lol_dba/issues/39) for more informations).

This issue has been addressed in [this
PR](https://github.com/plentz/lol_dba/pull/40) and pushed in `lol_dba`
`1.6.3`.