Handle issues with ruamel-yaml version pin

[opotowsky]

In PR #2403 , we needed to add a max version pin for ruamel.yaml: https://github.com/terrapower/armi/pull/2403/changes#diff-50c86b7ed8ac2cf95bd48334961bf0530cdc77b5a56f852c5c61b89d735fd711R43

v0.19.0 broke the code with:

This is a bug with RoundTripLoader. Right now we pass around loaders for a presumed speedup. The fix will involve us removing all passing around of loader and just using YAML() directly. Once we get the code working, we need to make sure it doesn't slow down CI in ARMI or downstream. (This shouldn't affect case runs, since yaml loading is only done at the beginning of the run)

[john-science]

Sorry what is the problem with the new YAML version pin? I don't understand the ticket.

You say:

v0.19.0 broke the code with:

But that is not broken in ARMI main. Is ARMI main breaking things for you downstream?

[opotowsky]

Oh sorry if I wasn't clear. CI was broken with the new ruamel.yaml release. ARMI main is not broken because we merged an emergency max version pin. I just included the failure we were seeing on CI for posterity.

This ticket is more to solve the underlying problem. Its no rush since we have the emergency fix. Updating the description with the plan for a fix.