Consider updating PyYAML

[Ms2ger]

We're on 3.11; current is 5.1.2.

[Ms2ger]

We'll need to deal with https://github.com/yaml/pyyaml/wiki/PyYAML-yaml.load(input)-Deprecation

[leobalter]

Ref #2277

[leobalter]

cc @jugglinmike.

I don't have any objection to this change. I would just need to check if breaks anything we currently have. Unfortunately, my time is assigned to other projects until Wednesday, so I can't see it immediately.