Bump httpx from 0.27.2 to 0.28.1

Bumps [httpx](https://github.com/encode/httpx) from 0.27.2 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@0.27.2...0.28.1)

Author: dependabot[bot]

poetry.lock

@@ -17,7 +17,7 @@ django-prometheus = "2.3.1"
 django-simple-bulma = "2.6.0"
 djangorestframework = "3.14.0"
 gunicorn = "23.0.0"
-httpx = "0.27.2"
+httpx = "0.28.1"
 markdown = "3.7"
 psycopg = {extras = ["binary"], version = "3.2.3"}
 pyjwt = {version = "2.10.1", extras = ["crypto"]}