Bump pymc from 4.2.0 to 4.2.1

Bumps [pymc](https://github.com/pymc-devs/pymc) from 4.2.0 to 4.2.1.
- [Release notes](https://github.com/pymc-devs/pymc/releases)
- [Changelog](https://github.com/pymc-devs/pymc/blob/main/RELEASE-NOTES.md)
- [Commits](pymc-devs/pymc@v4.2.0...v4.2.1)

---
updated-dependencies:
- dependency-name: pymc
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

requirements-dev.txt

@@ -1,7 +1,7 @@
 arviz
 clickhouse-driver
 flake8
-pymc==4.2.0
+pymc==4.2.1
 pytest
 pytest-cov
 # Temporary pin to fix Aesara import