The current version of the migrator is not compatible with the Spark version on EMR

[julienrf]

Currently, the migrator uses Scala 2.13 whereas EMR provides out-of-the-box support for Spark on Scala 2.12. This makes it impossible to use the Migrator on EMR using the built-in Spark images.

There two possible solutions:

1. Switch to Scala 2.12 in the migrator. This should be simple to do (maybe we have to add a dependency on scala-collection-compat).
2. Document how to build custom EMR images, or provide our own EMR images correctly pre-configured. This option needs to be investigated.