Update changelog.

Author: jonathantorres

CHANGELOG.md

@@ -1,13 +1,12 @@
 # Changelog
 
-#### v1.13.0 `2016-10-??`
+#### v1.13.0 `2016-12-11`
 - `Added`
     - Coding standard checks are only run against a single PHP version. Done by [@raphaelstolt](https://github.com/raphaelstolt).
     - PHP version `7.1` is added to Travis CI builds. Done by [@raphaelstolt](https://github.com/raphaelstolt).
     - Coding standard checks based on the PHP Coding Standards Fixer are cached and validated via Travis CI. Done by [@raphaelstolt](https://github.com/raphaelstolt) and initiated by [@localheinz](https://github.com/localheinz).
     - Composer dependencies are sorted. Done by [@raphaelstolt](https://github.com/raphaelstolt).
     - Composer dependencies are cached for Travis CI builds. Done by [@raphaelstolt](https://github.com/raphaelstolt).
-
 - `Fixed`
     - Aligned generated `.php_cs` configuration with `php-cs-fixer` ^2.0 release. Done by [@raphaelstolt](https://github.com/raphaelstolt).