update changelog before tagging

Author: alcohol

CHANGELOG.md

@@ -7,6 +7,10 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
   * ...
 
+## [1.5.1] 2019-03-26
+
+  * Changed: updated licenses list to SPDX 3.4
+
 ## [1.5.0] 2018-11-01
 
   * Changed: updated licenses list (SPDX 3.3)
@@ -69,7 +73,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
     - Classname: `Updater` -> `SpdxLicensesUpdater`
   * Changed: validation via regex implementation instead of lexer.
 
-[master]: https://github.com/composer/spdx-licenses/compare/1.5.0...master
+[master]: https://github.com/composer/spdx-licenses/compare/1.5.1...master
+[1.5.1]: https://github.com/composer/spdx-licenses/compare/1.5.0...1.5.1
 [1.5.0]: https://github.com/composer/spdx-licenses/compare/1.4.0...1.5.0
 [1.4.0]: https://github.com/composer/spdx-licenses/compare/1.3.0...1.4.0
 [1.3.0]: https://github.com/composer/spdx-licenses/compare/1.2.0...1.3.0