fix: move CI off ubuntu-20

Author: mobiusklein

.github/workflows/pythonpackage.yaml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         python-version: ['3.8', '3.9', '3.10', '3.11', '3.12']
-        os: [ubuntu-20.04, windows-2019, macos-latest]
+        os: [ubuntu-latest, windows-latest, macos-latest]
     steps:
     - uses: actions/checkout@v3
     - name: Set up Python ${{ matrix.python-version }}

.github/workflows/pythonpublish.yaml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       matrix:
         python-version: ['3.11']
-        os: [ubuntu-20.04, windows-2019, macos-latest]
+        os: [ubuntu-latest, windows-latest, macos-latest]
     steps:
     - uses: actions/checkout@v3
     - name: Set up Python ${{ matrix.python-version }}