Escapes html in content field (#189)

Author: lckr

README.md

@@ -2,6 +2,7 @@
 ![PyPi_Version](https://img.shields.io/pypi/v/lckr-jupyterlab-variableinspector)
 ![Build](https://github.com/lckr/jupyterlab-variableInspector/workflows/Build/badge.svg)
 [![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/gh/lckr/jupyterlab-variableInspector.git/master?urlpath=lab)
+[![GPLv3 License](https://img.shields.io/badge/License-GPL%20v3-yellow.svg)](https://opensource.org/licenses/)
 
 Jupyterlab extension that shows currently used variables and their values.  
 Contributions in any form are welcome!