Prepares CHANGELOG for 1.5.0 release

- Adds release date to 1.5.0 entry
- Removes empty 1.4.2 entry

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.
 
-## 1.5.0 - TBD
+## 1.5.0 - 2017-08-22
 
 ### Added
 
@@ -62,28 +62,6 @@ All notable changes to this project will be documented in this file, in reverse
   `Uri` class provides user-info within the URI authority; the value is now
   correctly percent-encoded , per RFC 3986 Section 3.2.1.
 
-## 1.4.2 - TBD
-
-### Added
-
-- Nothing.
-
-### Changed
-
-- Nothing.
-
-### Deprecated
-
-- Nothing.
-
-### Removed
-
-- Nothing.
-
-### Fixed
-
-- Nothing.
-
 ## 1.4.1 - 2017-08-17
 
 ### Added