Automatically fetch last version of a reference during compatibility or register task

[ImFlog]

In the 5.5.X versions, when have to add SchemaReferences when calling the compatibility task and the register task.
A schema reference requires that we pass a version to the registry.

That would be great if we could retrieve the latest version by default. See if we do It here or if we push the modification in the schema-registry API directly.

[ImFlog]

After investigation, I found that if you pass -1 as the version, it uses the last available version when resolving dependencies.
There is no need to change anything in our code base.

CC: @clatko-globe