Use Python 3.13 on Netlify

Author: InessaPawson

netlify.toml

@@ -1,7 +1,7 @@
 # Settings in the [build] context are global and are applied to all contexts
 # unless otherwise overridden by more specific contexts.
 [build.environment]
-  PYTHON_VERSION = "3.8" # netlify currently only support 2.7 and 3.8
+  PYTHON_VERSION = "3.13"
   HUGO_VERSION = "0.134.3"
   DART_SASS_VERSION = "1.77.5"
   DART_SASS_URL = "https://github.com/sass/dart-sass/releases/download/"