chore(deps): bump pyarrow from 20.0.0 to 21.0.0

Bumps [pyarrow](https://github.com/apache/arrow) from 20.0.0 to 21.0.0.
- [Release notes](https://github.com/apache/arrow/releases)
- [Commits](https://github.com/apache/arrow/compare/apache-arrow-20.0.0...apache-arrow-21.0.0)

---
updated-dependencies:
- dependency-name: pyarrow
  dependency-version: 21.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

requirements.txt

@@ -25,7 +25,7 @@ pycoingecko==3.2.0
 jinja2==3.1.6
 joblib==1.5.1
 rich==14.0.0
-pyarrow==20.0.0; platform_machine != 'armv7l'
+pyarrow==21.0.0; platform_machine != 'armv7l'
 
 # Load ticker files 30% faster
 python-rapidjson==1.21