Schema evolution script does not flag some evolutions as impossible

[tmadlener]

The podio_schema_evolution.py script should catch problematic schema evolutions before they are actually commited. The recent swtich from Vector3f to Vector3d in EDM4hep was one of these changes as it is not supported by default by ROOT. However, the output of the current version of the script simply states the following:

$ python3 ~/work/AIDASoft/podio/python/podio_schema_evolution.py edm4hep.yaml edm4hep_float_mom.yaml 
Comparing datamodel versions 1 and 1
Detected 2 schema changes:
 - 'edm4hep::MCParticle.momentum' changed type from '+                    'edm4hep::Vector3f to edm4hep::Vector3d
 - 'edm4hep::MCParticle.momentumAtEndpoint' changed type from '+                    'edm4hep::Vector3f to edm4hep::Vector3d
{}

This evolution should be flagged as impossible.

Related PRs / issues:

• Make MCParticle momenta use doubles instead of floats key4hep/EDM4hep#267 (plus PRs therein)
• Results of clic reconstruction changed for nightlies key4hep/k4MarlinWrapper#170 (what was broken by not realizing the issue early enough)