Run Windows and Mac jobs on upper-bound Py3.13 not 3.12

Author: CAM-Gerlach

.github/workflows/tests.yaml

@@ -64,7 +64,7 @@ jobs:
           - RUNNER_OS: 'windows'
             PYTHON_VERSION: '3.11'
           - RUNNER_OS: 'windows'
-            PYTHON_VERSION: '3.13'
+            PYTHON_VERSION: '3.12'
           - RUNNER_OS: 'windows'
             INSTALL_TYPE: 'pip'
           - RUNNER_OS: 'windows'
@@ -74,7 +74,7 @@ jobs:
           - RUNNER_OS: 'macos'
             PYTHON_VERSION: '3.11'
           - RUNNER_OS: 'macos'
-            PYTHON_VERSION: '3.13'
+            PYTHON_VERSION: '3.12'
           - RUNNER_OS: 'macos'
             INSTALL_TYPE: 'pip'
           - RUNNER_OS: 'macos'