Drop support for Python 3.8

This goes EOL in October. We don't want to be supporting it past then.
Drop it now.

Change-Id: I6166678a35092760718d4fcd0357e7195bbe8be0
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

.zuul.yaml

@@ -18,8 +18,8 @@
       zuul_work_dir: src/opendev.org/openstack/python-openstackclient
 
 - job:
-    name: osc-tox-py38-tips
+    name: osc-tox-py39-tips
-    parent: openstack-tox-py38
+    parent: openstack-tox-py39
     description: |
       Run unit tests for OpenStackClient with master branch of important libs.
 
@@ -201,11 +201,11 @@
     name: osc-tox-unit-tips
     check:
       jobs:
-        - osc-tox-py38-tips
+        - osc-tox-py39-tips
         - osc-tox-py312-tips
     gate:
       jobs:
-        - osc-tox-py38-tips
+        - osc-tox-py39-tips
         - osc-tox-py312-tips
 
 - project:

releasenotes/notes/drop-python-38-9dcbd2b2b51f24f2.yaml

@@ -0,0 +1,4 @@
+---
+upgrade:
+  - |
+    Support for Python 3.8 has been dropped.

setup.cfg

@@ -6,7 +6,7 @@ description_file =
 author = OpenStack
 author_email = openstack-discuss@lists.openstack.org
 home_page = https://docs.openstack.org/python-openstackclient/latest/
-python_requires = >=3.8
+python_requires = >=3.9
 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 :: 3.8
     Programming Language :: Python :: 3.9
     Programming Language :: Python :: 3.10
     Programming Language :: Python :: 3.11