docs(readme): Remove david-dm.org shield

Author: eheikes

README.md

@@ -12,7 +12,6 @@ These tools require an account with at least one of these (paid) services:
 
 [![Vulnerabilities](https://img.shields.io/snyk/vulnerabilities/npm/tts-cli)](https://snyk.io/vuln/npm:tts-cli)
 [![Build Status](https://img.shields.io/travis/eheikes/tts)](https://travis-ci.org/github/eheikes/tts)
-[![Dependencies](https://img.shields.io/david/eheikes/tts)](https://david-dm.org/eheikes/tts)
 [![Coverage](https://img.shields.io/codecov/c/gh/eheikes/tts?token=9bd5731ce1a34766bdf3d780a648fa05)](https://codecov.io/gh/eheikes/tts)
 [![License](https://img.shields.io/github/license/eheikes/tts)](https://github.com/eheikes/tts/blob/master/LICENSE.txt)