Possible issue when running test-and-upgrade with --skip-schemas

[3nids]

When running test-and-upgrade with --skip-schemas, the option will be used both for check and dump. See https://github.com/opengisch/pum/blob/master/scripts/pum#L327 It might be problematic when used with public (to avoid postgis comparison) as one would then need to create the postgis extension prior to the restore. To be investigated