feat: update Python version to 3.13 in configuration and documentation files

Author: ryan-gang

compiled_starters/python/README.md

@@ -30,7 +30,7 @@ Time to move on to the next stage!
 
 Note: This section is for stages 2 and beyond.
 
-1. Ensure you have `python (3.11)` installed locally
+1. Ensure you have `python (3.13)` installed locally
 1. Run `./your_program.sh` to run your program, which is implemented in
    `app/main.py`.
 1. Commit your changes and run `git push origin master` to submit your solution

solutions/python/01-at4/code/README.md

@@ -30,7 +30,7 @@ Time to move on to the next stage!
 
 Note: This section is for stages 2 and beyond.
 
-1. Ensure you have `python (3.11)` installed locally
+1. Ensure you have `python (3.13)` installed locally
 1. Run `./your_program.sh` to run your program, which is implemented in
    `app/main.py`.
 1. Commit your changes and run `git push origin master` to submit your solution

starter_templates/python/config.yml

@@ -1,3 +1,3 @@
 attributes:
-  required_executable: python (3.11)
+  required_executable: python (3.13)
   user_editable_file: app/main.py