docs: update travis badge to travis-ci.com

Author: sherwinski

README.md

@@ -4,7 +4,7 @@
 `imgix-php` is a client library for generating image URLs with [imgix](https://www.imgix.com/). It is tested under PHP versions `5.6`, `7.0`, `7.1`, and `7.2`
 
 [![Version](https://img.shields.io/packagist/v/imgix/imgix-php.svg)](https://packagist.org/packages/imgix/imgix-php)
-[![Build Status](https://travis-ci.org/imgix/imgix-php.svg?branch=main)](https://travis-ci.org/imgix/imgix-php)
+[![Build Status](https://travis-ci.com/imgix/imgix-php.svg?branch=main)](https://travis-ci.com/imgix/imgix-php)
 [![Downloads](https://img.shields.io/packagist/dt/imgix/imgix-php)](https://packagist.org/packages/imgix/imgix-php)
 [![License](https://img.shields.io/github/license/imgix/imgix-php)](https://github.com/imgix/imgix-php/blob/main/LICENSE)