[CLEANUP] Change the SemVer URL to HTTPS (#84)

Author: oliverklee

CHANGELOG.md

@@ -1,7 +1,7 @@
 # phpList 4 REST API change log
 
 All notable changes to this project will be documented in this file.
-This project adheres to [Semantic Versioning](http://semver.org/).
+This project adheres to [Semantic Versioning](https://semver.org/).
 
 
 ## 4.0.0 (unreleased)