Remove newsletter badge

Author: thinkingserious

README.md

@@ -2,7 +2,6 @@
 
 [![Travis Badge](https://travis-ci.com/sendgrid/php-http-client.svg?branch=main)](https://travis-ci.com/sendgrid/php-http-client)
 [![Latest Version on Packagist](https://img.shields.io/packagist/v/sendgrid/php-http-client.svg?style=flat-square)](https://packagist.org/packages/sendgrid/php-http-client)
-[![Email Notifications Badge](https://dx.sendgrid.com/badge/php)](https://dx.sendgrid.com/newsletter/php)
 [![Twitter Follow](https://img.shields.io/twitter/follow/sendgrid.svg?style=social&label=Follow)](https://twitter.com/sendgrid)
 [![GitHub contributors](https://img.shields.io/github/contributors/sendgrid/php-http-client.svg)](https://github.com/sendgrid/php-http-client/graphs/contributors)
 [![MIT licensed](https://img.shields.io/badge/license-MIT-blue.svg)](LICENSE)