add security file

Author: jhrutgers

SECURITY.md

@@ -0,0 +1,9 @@
+<!---
+SPDX-FileCopyrightText: 2024 Jochem Rutgers
+   
+SPDX-License-Identifier: CC0-1.0
+-->
+
+# Reporting Security Issues
+
+To report a security issue, please use the GitHub Security Advisory ["Report a Vulnerability"](https://github.com/DEMCON/cmake-sbom/security/advisories/new) tab.