Update ChangeLog

Author: sebastianbergmann

ChangeLog-4.8.md

@@ -7,6 +7,7 @@ All notable changes of the PHPUnit 4.8 release series are documented in this fil
 ### Fixed
 
 * Fixed [#1983](https://github.com/sebastianbergmann/phpunit/pull/1983): Tests with `@expectedException` annotation cannot be skipped
+* Fixed [#2275](https://github.com/sebastianbergmann/phpunit/pull/2275): Invalid UTF-8 characters can lead to missing output
 * Fixed [#2331](https://github.com/sebastianbergmann/phpunit/issues/2331): Boolean environment variable values specified in XML get mangled
 * Fixed [#2431](https://github.com/sebastianbergmann/phpunit/issues/2431): `assertArraySubset()` does not support `ArrayAccess`