Push assert library up the list to maintain alphabetical sorting

README.md

 ## Filtering and Validation
 *Libraries for filtering and validating data.*
 
+* [Assert](https://github.com/beberlei/assert) - A validation library with a rich set of assertions. Supports assertion chaining and lazy assertions.
 * [Cake Validation](https://github.com/cakephp/validation) - Another validation library (CP).
 * [DMS Filter](https://github.com/rdohms/DMS-Filter) - An annotation filtering library.
 * [Filterus](https://github.com/ircmaxell/filterus) - A simple PHP filtering library.
 * [Upload](https://github.com/brandonsavage/Upload) - A library for handling file uploads and validation.
 * [Valitron](https://github.com/vlucas/valitron) - Another validation library.
 * [Volan](https://github.com/serkin/Volan) - Another simplified validation library.
-* [Assert](https://github.com/beberlei/assert) - A validation library with a rich set of assertions. Supports assertion chaining and lazy assertions.
 
 ## API
 *Libraries and web tools for developing APIs.*