Upgrade GitHub actions versions in workflow

A manual alternative to:
* encode#1031
* https://github.com/actions/checkout/releases
* https://github.com/actions/setup-python/releases

Author: cclauss

.github/workflows/test-suite.yml

@@ -17,8 +17,8 @@ jobs:
         python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
 
     steps:
-      - uses: "actions/checkout@v4"
-      - uses: "actions/setup-python@v4"
+      - uses: "actions/checkout@v5"
+      - uses: "actions/setup-python@v6"
         with:
           python-version: "${{ matrix.python-version }}"
           allow-prereleases: true