fix: add missing packaging dependency

The replicate.lib._schema module imports the packaging library
but it wasn't listed as a dependency in pyproject.toml, causing
ModuleNotFoundError when the module is imported.

Fixes import error: "ModuleNotFoundError: No module named 'packaging'"

Author: zeke

pyproject.toml

@@ -14,6 +14,7 @@ dependencies = [
     "anyio>=3.5.0, <5",
     "distro>=1.7.0, <2",
     "sniffio",
+    "packaging>=25.0",
 ]
 requires-python = ">= 3.8"
 classifiers = [