Bump pandas from 2.1.0 to 2.1.1 (#946)

Bumps [pandas](https://github.com/pandas-dev/pandas) from 2.1.0 to 2.1.1.
- [Release notes](https://github.com/pandas-dev/pandas/releases)
- [Commits](pandas-dev/pandas@v2.1.0...v2.1.1)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements/requirements-test-optional.txt

@@ -1,5 +1,5 @@
 h5py==3.9.0; implementation_name=='cpython'
 numpy==1.25.2
-pandas==2.1.0; implementation_name=='cpython'
+pandas==2.1.1; implementation_name=='cpython'
 ruamel.yaml==0.17.32
 tables==3.8.0; implementation_name=='cpython'