Update changelog #74 (#247)

Author: Jannis-Mittenzwei

doc/changes/changes_0.15.0.md

@@ -4,6 +4,7 @@
 
 * Added cookiecutter-template for creating new project
 * [#246](https://github.com/exasol/python-toolbox/issues/246): Added standard branch protection workflow
+* #74: Added security linter nox task
 
 ## 🐞 Bug Fixes