Bump scipp from 26.1.0 to 26.2.0 in /requirements

Bumps [scipp](https://github.com/scipp/scipp) from 26.1.0 to 26.2.0.
- [Release notes](https://github.com/scipp/scipp/releases)
- [Commits](scipp/scipp@26.1.0...26.2.0)

---
updated-dependencies:
- dependency-name: scipp
  dependency-version: 26.2.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

requirements/base.txt

@@ -49,7 +49,7 @@ python-dateutil==2.9.0.post0
     # via matplotlib
 requests==2.32.5
     # via pooch
-scipp==26.1.0
+scipp==26.2.0
     # via -r base.in
 six==1.17.0
     # via python-dateutil

requirements/basetest.txt

@@ -70,7 +70,7 @@ python-dateutil==2.9.0.post0
     # via
     #   matplotlib
     #   scippneutron
-scipp==26.1.0
+scipp==26.2.0
     # via
     #   scippneutron
     #   scippnexus