pip prod(deps): update pandas requirement

Updates the requirements on [pandas](https://github.com/pandas-dev/pandas) to permit the latest version.
- [Release notes](https://github.com/pandas-dev/pandas/releases)
- [Commits](pandas-dev/pandas@v1.0.3...v2.1.2)

---
updated-dependencies:
- dependency-name: pandas
  dependency-type: direct:production
...

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

requirements.txt

@@ -2,7 +2,7 @@ pip
 airr
 setuptools_scm[toml]>=6.0
 numpy>=1.18.4
-pandas>=1.0.3,<=2.1.1
+pandas>=1.0.3,<=2.1.2
 changeo>=1.0.0
 anndata>=0.7.1
 scanpy>=1.4.6