Fix python_requires in setup.cfg. (#559)

changelogs/fragments/559-python_requires.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - "Use the correct directive in ``setup.cfg`` for Ansible 9+ for requiring a Python version, i.e. use ``python_requires`` instead of ``requires_python`` (https://github.com/ansible-community/antsibull/pull/559)."

src/antsibull/python_metadata.py

@@ -293,7 +293,7 @@ def generate(self) -> None:
             f"ansible-core ~= {self.ansible_core_version}"
         )
 
-        self["options"]["requires_python"] = (
+        self["options"]["python_requires"] = (
             self.python_requires or self.core_python_requires
         )
 
@@ -363,7 +363,7 @@ def write(self, file: Path | None = None) -> None:
             # pylint: disable-next=protected-access
             collection_directories=self.maker._collection_directories,
             #
-            python_requires=self.maker["options"]["requires_python"],
+            python_requires=self.maker["options"]["python_requires"],
             PypiVer=PypiVer,
         )
         file.write_text(setup_contents, encoding="utf-8")

tests/test_data/package-files/force_setup_cfg/8.1.0/setup.cfg

@@ -34,7 +34,7 @@ project_urls =
 zip_safe = False
 install_requires = 
 	  ansible-core ~= 2.15.1
-requires_python = >=3.9
+python_requires = >=3.9
 package_dir = 
 	=.
 packages = find_namespace: