Bump scippnexus from 24.8.0 to 24.8.1 in /requirements

Bumps [scippnexus](https://github.com/scipp/scippnexus) from 24.8.0 to 24.8.1.
- [Release notes](https://github.com/scipp/scippnexus/releases)
- [Commits](scipp/scippnexus@24.08.0...24.08.1)

---
updated-dependencies:
- dependency-name: scippnexus
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

requirements/base.txt

@@ -48,7 +48,7 @@ scipp==24.6.0
     # via
     #   -r base.in
     #   scippnexus
-scippnexus==24.8.0
+scippnexus==24.8.1
     # via -r base.in
 scipy==1.14.0
     # via