Drop support for Python 3.8

Python 3.8 went "end of life" in October 2024 and Fedora 42 dropped
this version already, so the "python" CI job is currently failing.
Thus it's time to drop support for this Python version in QEMU, too.

While we're at it, also look for "python3.13" in the configure script.

Message-ID: <20250425120710.879518-1-thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
(cherry picked from commit d64db833d6)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

python/setup.cfg

@@ -14,7 +14,6 @@ classifiers =
     Natural Language :: English
     Operating System :: OS Independent
     Programming Language :: Python :: 3 :: Only
-    Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
     Programming Language :: Python :: 3.10
     Programming Language :: Python :: 3.11
@@ -23,7 +22,7 @@ classifiers =
     Typing :: Typed
 
 [options]
-python_requires = >= 3.8
+python_requires = >= 3.9
 packages =
     qemu.qmp
     qemu.machine
@@ -78,7 +77,7 @@ exclude = __pycache__,
 
 [mypy]
 strict = True
-python_version = 3.8
+python_version = 3.9
 warn_unused_configs = True
 namespace_packages = True
 warn_unused_ignores = False
@@ -186,7 +185,7 @@ multi_line_output=3
 # of python available on your system to run this test.
 
 [tox:tox]
-envlist = py38, py39, py310, py311, py312, py313
+envlist = py39, py310, py311, py312, py313
 skip_missing_interpreters = true
 
 [testenv]