chore(deps): bump openai from 2.6.1 to 2.8.1 in /requirements/in

Bumps [openai](https://github.com/openai/openai-python) from 2.6.1 to 2.8.1.
- [Release notes](https://github.com/openai/openai-python/releases)
- [Changelog](https://github.com/openai/openai-python/blob/main/CHANGELOG.md)
- [Commits](openai/openai-python@v2.6.1...v2.8.1)

---
updated-dependencies:
- dependency-name: openai
  dependency-version: 2.8.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

requirements/in/base.in

@@ -9,7 +9,7 @@
 
 -r constraints.in
 
-openai==2.6.1
+openai==2.8.1
 python-dotenv==1.2.1
 PyMySQL==1.1.2
 pydantic==2.12.2