Bump httpx from 0.23.3 to 0.28.1 (#943)

Bumps [httpx](https://github.com/encode/httpx) from 0.23.3 to 0.28.1.
- [Release notes](https://github.com/encode/httpx/releases)
- [Changelog](https://github.com/encode/httpx/blob/master/CHANGELOG.md)
- [Commits](encode/httpx@0.23.3...0.28.1)

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

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

requirements.txt

@@ -28,4 +28,4 @@ discord.py==2.4.0
 git+https://github.com/cemathey/django-directory@f51ee1e8dc50edf453fee4a0d9631c0e46fe9433
 pre-commit
 humanize==4.12.0
-httpx==0.23.3
+httpx==0.28.1