[v1.x] build: restrict httpx to <1.0.0 (#2559)

pyproject.toml

@@ -23,7 +23,7 @@ classifiers = [
 ]
 dependencies = [
     "anyio>=4.5",
-    "httpx>=0.27.1",
+    "httpx>=0.27.1,<1.0.0",
     "httpx-sse>=0.4",
     "pydantic>=2.11.0,<3.0.0",
     "starlette>=0.27",

uv.lock

@@ -819,7 +819,7 @@ docs = [
 [package.metadata]
 requires-dist = [
     { name = "anyio", specifier = ">=4.5" },
-    { name = "httpx", specifier = ">=0.27.1" },
+    { name = "httpx", specifier = ">=0.27.1,<1.0.0" },
     { name = "httpx-sse", specifier = ">=0.4" },
     { name = "jsonschema", specifier = ">=4.20.0" },
     { name = "pydantic", specifier = ">=2.11.0,<3.0.0" },