fix: looser constraints on httpx

Author: tractorcow

pyproject.toml

@@ -18,7 +18,7 @@ Changelog = "https://github.com/MarcoMuellner/openapi-python-generator/releases"
 
 [tool.poetry.dependencies]
 python = "^3.8"
-httpx = {extras = ["all"], version = "^0.23.0"}
+httpx = {extras = ["all"], version = ">=0.23.0,<1.0.0"}
 pydantic = "^2.10.2"
 orjson = "^3.9.15"
 Jinja2 = "^3.1.2"