update TOC?

Author: josesho

README.md

@@ -6,7 +6,7 @@
 [![Free-to-view citation](https://zenodo.org/badge/DOI/10.1038/s41592-019-0470-3.svg)](https://rdcu.be/bHhJ4)
 [![License](https://img.shields.io/badge/License-BSD%203--Clause--Clear-orange.svg)](https://spdx.org/licenses/BSD-3-Clause-Clear.html)
 
-# Contents
+## Contents
 <!-- TOC depthFrom:1 depthTo:2 withLinks:1 updateOnSave:1 orderedList:0 -->
 - [About](#about)
 - [Installation](#installation)