Fix the python matrix to be strings.

Author: nedtwigg

.github/workflows/python-ci.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.8, 3.9, 3.10, 3.11, 3.12]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
         os: [ubuntu-latest, windows-latest]
     runs-on: ${{ matrix.os }}
     steps: