add 2020 microgames to sidebar

Author: Adimote

_data/sidebar_tree.yaml

@@ -102,6 +102,8 @@ tree:
     tree:
     - url: /tutorials/basic_motor_control
       title: Basic Motor Control
+    - url: /tutorials/2020_microgames
+      title: SR2020 Microgames
     - url: /tutorials/python
       title: Python
   - url: /team_admin/