feat: support py typed (#51)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: tomsun28

pyproject.toml

@@ -5,6 +5,7 @@ description = "A SDK library for accessing big model apis from Z.ai"
 authors = ["Z.ai"]
 readme = "README.md"
 packages = [{include = "zai", from = "src"}]
+include = ["zai/py.typed"]
 
 [tool.poetry.dependencies]
 python = ">=3.8,<4.0.0,!=3.9.7 "