build(deps): bump prometheus-client from 0.20.0 to 0.21.0 (#141)

Bumps [prometheus-client](https://github.com/prometheus/client_python) from 0.20.0 to 0.21.0.
- [Release notes](https://github.com/prometheus/client_python/releases)
- [Commits](prometheus/client_python@v0.20.0...v0.21.0)

---
updated-dependencies:
- dependency-name: prometheus-client
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

requirements.txt

@@ -19,7 +19,7 @@ packaging==24.0
 pandas==2.2.2
 pillow==10.3.0
 prometheus-api-client==0.5.5
-prometheus-client==0.20.0
+prometheus-client==0.21.0
 pydantic==1.10.18
 pydantic-yaml==0.11.2
 pyparsing==3.1.2