Update changelog.

Author: jonathantorres

CHANGELOG.md

@@ -1,6 +1,6 @@
 # Changelog
 
-#### v1.13.1 `2017-0?-??`
+#### v1.13.1 `2017-03-01`
 - `Fixed`
     - Fix generated PHP Coding Standards Fixer configuration. Done by [@raphaelstolt](https://github.com/raphaelstolt). See [#172](https://github.com/jonathantorres/construct/issues/172).
     - Executable test skeleton for PHPUnit 6. Done by [@raphaelstolt](https://github.com/raphaelstolt). See [#170](https://github.com/jonathantorres/construct/issues/170).