Update pyproject.toml

Co-authored-by: Copilot <[email protected]>

Author: xiangfu0

pyproject.toml

@@ -11,7 +11,7 @@ homepage = "https://github.com/python-pinot-dbapi/pinot-dbapi"
 [tool.poetry.dependencies]
 python = ">=3.8,<4"
 ciso8601 = "^2.1.3"
-httpx = "0.28.1"
+httpx = ">=0.28.1,<0.29"
 sqlalchemy = {version = ">=1.4,<2", optional = true}
 requests = "^2.25.0"
 # Explicitly pinning h11 to version 0.16.0 to override a CVE-affected transitive dependency in httpx.