build(deps): update httpx requirement from <0.28 to <0.29

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@0.0.1...0.28.1)

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

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

pyproject.toml

@@ -43,7 +43,7 @@ dynamic = [
   "version",
 ]
 dependencies = [
-  "httpx<0.28",   # this is pinned temporarily, until respx is able to mock 0.28+ properly
+  "httpx<0.29",   # this is pinned temporarily, until respx is able to mock 0.28+ properly
   "xsdata>=24.5",
 ]
 optional-dependencies.cli = [