update preview image

Author: echarles

README.md

@@ -1,13 +1,9 @@
 # JupyterLab Kernel Usage
 
-[![Github Actions Status](https://github.com/quansight/jupyterlab-kernel-usage/workflows/Build/badge.svg)](https://github.com/quansight/jupyterlab-kernel-usage/actions/workflows/build.yml)
-
-This is an extension for JupyterLab which allows to get kernel usage in a JupyerLab sidebar.
+This is an extension for [JupyterLab](https://github.com/jupyterlab/jupyterlab) to get kernel usage in a sidebar.
 
 ![JupyterLab Kernel Usage](./images/preview.gif)
 
-> For now, you will need to "bootstrap" the sidebar clicking between 2 notebooks so the values show up and refresh. Do that only the first time you make the sidebar visible.
-
 This extension is composed of a Python package named `jupyterlab_kernel_usage` for the server extension and a NPM package named `jupyterlab-kernel-usage` for the frontend extension.
 
 ## Contributing