Make the CI cover Python 3.14

Author: hartwork

.github/workflows/build.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ['3.8', '3.12']  # oldest and youngest Pythons alive
+        python-version: ['3.8', '3.14']  # oldest and youngest Pythons alive
     steps:
     - uses: actions/checkout@v4
       with: