Add scalable cma-mae tutorial to TOC (#443)

## Description

<!-- Provide a brief description of the PR's purpose here. -->

Forgot to add to the TOC in #433

## Status

- [x] I have read the guidelines in

[CONTRIBUTING.md](https://github.com/icaros-usc/pyribs/blob/master/CONTRIBUTING.md)
- [x] I have formatted my code using `yapf`
- [x] I have tested my code by running `pytest`
- [x] I have linted my code with `pylint`
- [x] I have added a one-line description of my change to the changelog
in
      `HISTORY.md`
- [x] This PR is ready to go

HISTORY.md

@@ -58,7 +58,7 @@ Small release that adds the scalable CMA-MAE tutorial.
 
 #### Documentation
 
-- Add tutorial on scalable CMA-MAE variants ({pr}`433`)
+- Add tutorial on scalable CMA-MAE variants ({pr}`433`, {pr}`443`)
 
 ## 0.6.3
 

docs/tutorials.md

@@ -13,6 +13,7 @@ tutorial page has a link to open the tutorial in Google Colab.
 tutorials/lunar_lander
 tutorials/cma_mae
 tutorials/tom_cruise_dqd
+tutorials/scalable_cma_mae
 ```
 
 These tutorials demonstrate how to use the key algorithms in pyribs. We