Change badge wording to pds compliant

[raphaelstolt]

Wouldn't it be more appropriate to change the badge wording to pds compliant?

[![PDS compliant](https://img.shields.io/badge/pds-compliant-blue.svg?style=flat-square)](https://github.com/php-pds/skeleton)

[ellisgl]

Also, I'll leave this here: https://github.com/badges/shields