Include py.typed when packaging. (#338)

* Include py.typed when packaging.

* Update changelog

Author: clokep

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## Unreleased
+### Packaging
+- Include `py.typed` when packaging to denote that setuptools-rust includes type hints. [#338](https://github.com/PyO3/setuptools-rust/pull/338)
+
 ## 1.6.0 (2023-04-27)
 ### Changed
 - Prefer passing `--crate-type` option to cargo if "toolchain >= 1.64". [#322](https://github.com/PyO3/setuptools-rust/pull/322)

pyproject.toml

@@ -56,3 +56,6 @@ addopts = "--doctest-modules"
 [tool.setuptools]
 packages = ["setuptools_rust"]
 zip-safe = true
+
+[tool.setuptools.package-data]
+setuptools_rust = ["py.typed"]