Remove py39 reference from setup.cfg

Change-Id: Ica76dbf2ea70f69574e2085299de965c33a51d7d

releasenotes/notes/drop-py39-fbdd3fd504153a18.yaml

@@ -0,0 +1,7 @@
+---
+upgrade:
+  - |
+    Python 3.9 support has been dropped. The last release of neutron-fwaas
+    to support py39 is Openstack 2025.1 (Epoxy).
+    For details about supported runtimes in Openstack 2025.2 please check:
+    https://governance.openstack.org/tc/reference/runtimes/2025.2.html

setup.cfg

@@ -6,7 +6,7 @@ description_file =
 author = OpenStack
 author_email = openstack-discuss@lists.openstack.org
 home_page = https://docs.openstack.org/neutron-fwaas/latest/
-python_requires = >=3.9
+python_requires = >=3.10
 classifier =
     Environment :: OpenStack
     Intended Audience :: Information Technology
@@ -15,7 +15,6 @@ classifier =
     Operating System :: POSIX :: Linux
     Programming Language :: Python
     Programming Language :: Python :: 3
-    Programming Language :: Python :: 3.9
     Programming Language :: Python :: 3.10
     Programming Language :: Python :: 3.11
     Programming Language :: Python :: 3.12