Bump pandas from 2.2.3 to 2.3.1

Bumps [pandas](https://github.com/pandas-dev/pandas) from 2.2.3 to 2.3.1.
- [Release notes](https://github.com/pandas-dev/pandas/releases)
- [Commits](pandas-dev/pandas@v2.2.3...v2.3.1)

---
updated-dependencies:
- dependency-name: pandas
  dependency-version: 2.3.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements.txt

@@ -1,6 +1,6 @@
 # This is used to build the CI test environment and so Github can track dependencies.
 xarray==2025.1.2
-pandas==2.2.3
+pandas==2.3.1
 numpy==1.26.4
 matplotlib==3.10.1
 dask[array, distributed]==2025.2.0