message: added new downloads badge
diff: -[![Open Source Love](https://badges.frapsoft.com/os/v1/open-source.svg?v=103)](https://github.com/ellerbrock/open-source-badge/) [![MIT Licence](https://badges.frapsoft.com/os/mit/mit.svg?v=103)](https://opensource.org/licenses/mit-license.php) [![npm version](https://badge.fury.io/js/pptxgenjs.svg)](https://badge.fury.io/js/pptxgenjs)
  +[![Open Source Love](https://badges.frapsoft.com/os/v1/open-source.svg?v=103)](https://github.com/ellerbrock/open-source-badge/) [![MIT Licence](https://badges.frapsoft.com/os/mit/mit.svg?v=103)](https://opensource.org/licenses/mit-license.php) [![npm version](https://badge.fury.io/js/pptxgenjs.svg)](https://badge.fury.io/js/pptxgenjs) [![npm downloads](https://img.shields.io/npm/dm/pptxgenjs.svg)
  # PptxGenJS
  