GitHub Actions: Turn off fail-fast so we can see all failures

GitHub actions are currently failing, so let's examine all errors.

`build: strategy: fail-fast: false`
* https://docs.github.com/en/actions/reference/workflows-and-actions/workflow-syntax#jobsjob_idstrategyfail-fast

Author: cclauss

.github/workflows/test.yml

@@ -10,13 +10,14 @@ jobs:
     runs-on: ubuntu-latest
 
     strategy:
+      fail-fast: false
       matrix:
         python-version: ['3.8', '3.9', '3.10', '3.11', '3.12', '3.13']
 
     steps:
     - uses: actions/checkout@v5
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies