Update ROCm instructions to reference the latest version

[ScatteredComet]

This updates the referenced ROCm version to a modern, maintained version that works with Blender 5.0.0.

[thomas-zimmerman]

LGTM ; not seeing any oddness in a live test of the support site.

[jacobgkau]

The first sudo prompt was silent because wget was clobbering the terminal with its output. Adding -q works around this (I didn't see an easy solution to keep wget's output visible that doesn't require installing non-default packages first).

Updated the next command to work on any Ubuntu release by reading the system's codename instead of having it hard-coded. This works for at least 22.04 and 24.04, which is what the header will now show.

[jacobgkau]

I've tested that this works on both a 22.04 system and a 24.04 system.

It sounds like this hopefully won't be necessary anymore with 26.04, as Ubuntu has plans for first-party packaging: https://canonical.com/blog/canonical-amd-rocm-ai-ml-hpc-libraries