Update documentation

Author: Ayuto

addons/source-python/docs/source-python/source/index.rst

@@ -11,7 +11,7 @@ any questions, please search for an answer on our
 answer to your question, please post a question of your own in the appropriate
 forum.
 
-Source.Python is currently embedding Python 3.6.1 and will be upgraded from
+Source.Python is currently embedding Python 3.13 and will be upgraded from
 time to time.