Test CI against 3.15

Author: davesteele

.github/workflows/devtest.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
+        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14", "3.15.0-alpha - 3.15.0"]
     steps:
     - name: Check out
       uses: actions/checkout@v5