Adjust docs auto-generation dependency locks to accommodate Python 3.9.

Author: lapets

pyproject.toml

@@ -20,9 +20,9 @@ Documentation = "https://parts.readthedocs.io"
 [project.optional-dependencies]
 docs = [
     "toml~=0.10.2",
-    "sphinx~=8.0",
+    "sphinx~=7.4",
     "sphinx-rtd-theme~=3.0",
-    "sphinx-autodoc-typehints~=3.2"
+    "sphinx-autodoc-typehints~=2.3"
 ]
 test = [
     "pytest~=7.4; python_version < '3.12'",