Bump pandas from 2.1.1 to 2.1.3

Bumps [pandas](https://github.com/pandas-dev/pandas) from 2.1.1 to 2.1.3.
- [Release notes](https://github.com/pandas-dev/pandas/releases)
- [Commits](pandas-dev/pandas@v2.1.1...v2.1.3)

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

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==2023.10.1
-pandas==2.1.1
+pandas==2.1.3
 numpy==1.26.1
 matplotlib==3.8.0
 dask[array, distributed]==2023.10.0