CI: Update minimum python version to 3.9.

Let's see if this lets the tests pass.

Author: DWesl

.github/workflows/ci.yml

@@ -60,7 +60,7 @@ jobs:
     strategy:
       matrix:
         python:
-        - "3.8"  # oldest Python supported by PSF
+        - "3.9"  # oldest Python supported by PSF
         - "3.12"  # newest Python that is stable
         platform:
         - ubuntu-latest

pyproject.toml

@@ -30,7 +30,7 @@ classifiers = [
 dependencies = ['importlib-metadata; python_version<"3.8"']
 dynamic = ["version"]
 # Require a min/specific Python version (comma-separated conditions)
-# python_requires = [">=3.8"]
+requires-python = ">=3.9"
 
 [project.readme]
 file = "README.rst"