Update README.md (#24)

Update branch name to `main`

README.md

@@ -2,14 +2,14 @@
 
 [![Extension status](https://img.shields.io/badge/status-ready-success 'ready to be used')](https://jupyterlab-contrib.github.io/)
 [![Github Actions Status](https://github.com/jupyterlab-contrib/jupyterlab-favorites/workflows/Build/badge.svg)](https://github.com/jupyterlab-contrib/jupyterlab-favorites/actions?query=workflow%3ABuild)
-[![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/gh/jupyterlab-contrib/jupyterlab-favorites/master?urlpath=lab)
+[![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/gh/jupyterlab-contrib/jupyterlab-favorites/main?urlpath=lab)
 [![npm](https://img.shields.io/npm/v/@jlab-enhanced/favorites)](https://www.npmjs.com/package/@jlab-enhanced/favorites)
 [![PyPI](https://img.shields.io/pypi/v/jupyterlab-favorites)](https://pypi.org/project/jupyterlab-favorites)
 [![conda-forge](https://img.shields.io/conda/vn/conda-forge/jupyterlab-favorites)](https://anaconda.org/conda-forge/jupyterlab-favorites)
 
 Add the ability to save favorite folders to JupyterLab for quicker browsing.
 
-![JupyterLab Favorites extension demonstration](https://raw.githubusercontent.com/jupyterlab-contrib/jupyterlab-favorites/master/jupyterlab-favorites.gif)
+![JupyterLab Favorites extension demonstration](https://raw.githubusercontent.com/jupyterlab-contrib/jupyterlab-favorites/main/jupyterlab-favorites.gif)
 
 ## Requirements