Test with official 3.13 and 3.14 alphas

This change updates the unit testing to use the official
Python 3.13 released yesterday (Oct 7). It also starts
testing against the alpha versions of Python 3.14 to
catch potential problems early before it is officially released.

Signed-off-by: Eric Brown <eric_wade_brown@yahoo.com>

.github/workflows/pythonpackage.yml

@@ -51,7 +51,8 @@ jobs:
           ["3.10", "310"],
           ["3.11", "311"],
           ["3.12", "312"],
-          ["3.13.0-a - 3.13", "313"],
+          ["3.13", "313"],
+          ["3.14.0-alpha - 3.14", "314"],
         ]
         os: [ubuntu-latest, macos-latest]
     runs-on: ${{ matrix.os }}