Bump bandersnatch to 8.0 and bump required python_version to >=3.12

[gerrod3]

Generated-by: cursor-grok-4.6

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[gerrod3]

Seems like we will need changes to the plugin template, at least the build step will need to use python 3.12 so that it can install the built wheel. Should we bump for everyone? make it a new template config? add logic to determine the plugin's minimal required python? Since the ci-centos-10 image already uses py3.12, I think we should just bump it for every plugin using that image.