Bump nvidia/cuda from 12.6.2-base-ubi8 to 12.8.1-base-ubi8 in /fedora

Bumps nvidia/cuda from 12.6.2-base-ubi8 to 12.8.1-base-ubi8.

---
updated-dependencies:
- dependency-name: nvidia/cuda
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

fedora/Dockerfile

@@ -1,6 +1,6 @@
 ARG FEDORA_VERSION=36
 
-FROM nvcr.io/nvidia/cuda:12.6.2-base-ubi8 as build
+FROM nvcr.io/nvidia/cuda:12.8.1-base-ubi8 as build
 
 ARG TARGETARCH