Bump MSRV requirements

[prestist]

With the latest version of ignition-config-rs we stumbled into some of our dep's not being offered downstream do to our MSRV requirement being too old. Lets update MSRV and then trigger a re-build for both of these projects.

[travier]

RHEL 9.6 is stuck on 1.84.1 so if we want to keep backports easy, we should stay on this version. Otherwise, we can lock on what's in RHEL 9.8.