Point GitHub Actions build to correct Ubuntu image for older Python versions

Author: riggsd

.github/workflows/python-tests.yml

@@ -8,11 +8,30 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.6", "3.7", "3.8", "3.9", "3.10", "3.11", "3.12", "pypy-3.9"]
+        # Older Python versions on Ubuntu 20.04
+        - python-version: "3.6"
+          os: ubuntu-20.04
+        - python-version: "3.7"
+          os: ubuntu-20.04
+
+        # Newer Python versions on latest Ubuntu
+        - python-version: "3.8"
+          os: ubuntu-24.04
+        - python-version: "3.9"
+          os: ubuntu-24.04
+        - python-version: "3.10"
+          os: ubuntu-24.04
+        - python-version: "3.11"
+          os: ubuntu-24.04
+        - python-version: "3.12"
+          os: ubuntu-24.04
+        - python-version: "pypy-3.9"
+          os: ubuntu-24.04
+
+    runs-on: ${{ matrix.os }}
 
     steps:
     - uses: actions/checkout@v3

README.rst

@@ -37,7 +37,7 @@ locally in developer mode to hack on it yourself::
     $> cd guano-py
     $> python setup.py develop
 
-|Documentation Status|
+|Master Tests| |Dev Tests| |Documentation Status|
 
 
 API Usage
@@ -91,5 +91,9 @@ API Usage
 .. _GUANO: http://guano-md.org
 .. _useful scripts: bin/
 
+.. |Master Tests| image:: https://github.com/riggsd/guano-py/actions/workflows/python-tests.yml/badge.svg?branch=master
+   :target: https://github.com/riggsd/guano-py/actions/workflows/python-tests.yml?query=branch%3Amaster
+.. |Dev Tests| image:: https://github.com/riggsd/guano-py/actions/workflows/python-tests.yml/badge.svg?branch=dev
+   :target: https://github.com/riggsd/guano-py/actions/workflows/python-tests.yml?query=branch%3Adev
 .. |Documentation Status| image:: https://readthedocs.org/projects/guano-py/badge/?version=latest
    :target: http://guano-py.readthedocs.io/en/latest/?badge=latest