Updated CHANGELOG

- Set date for 2.6.0.
- Merged 2.5.2 and 2.6.0 entries, as I'm skipping 2.5.2.

Author: weierophinney

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 All notable changes to this project will be documented in this file, in reverse chronological order by release.
 
-## 2.6.0 - TBD
+## 2.6.0 - 2015-07-23
 
 ### Added
 
@@ -20,24 +20,6 @@ All notable changes to this project will be documented in this file, in reverse
 
 ### Fixed
 
-- Nothing.
-
-## 2.5.2 - TBD
-
-### Added
-
-- Nothing.
-
-### Deprecated
-
-- Nothing.
-
-### Removed
-
-- Nothing.
-
-### Fixed
-
 - [#3](https://github.com/zendframework/zend-servicemanager/pull/3) properly updates the
   codebase to PHP 5.5, by taking advantage of the default closure binding
   (`$this` in a closure is the invoking object when created within a method). It