Update httpx requirement from <=0.27.2,>=0.25.0 to >=0.25.0,<=0.28.1

Updates the requirements on [httpx](https://github.com/encode/httpx) to permit the latest version.
- [Release notes](https://github.com/encode/httpx/releases)
- [Changelog](https://github.com/encode/httpx/blob/master/CHANGELOG.md)
- [Commits](encode/httpx@0.25.0...0.28.1)

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

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

requirements.txt

@@ -1,5 +1,5 @@
 scikit-learn>=1.3.1,<=1.6.1
-httpx>=0.25.0,<=0.27.2
+httpx>=0.25.0,<=0.28.1
 omegaconf>=2.1.2,<=2.3.0
 pandas>=2.1.2,<=2.2.3
 password-strength>=0.0.3.post2,<=0.0.3.post2