docs: add SECURITY.md

Author: ChristianGalla

SECURITY.md

@@ -0,0 +1,21 @@
+# Security Policy
+
+## Supported Versions
+
+The following versions are currently being supported with security updates.
+
+| Version | Supported          |
+| ------- | ------------------ |
+| 3   | :white_check_mark: |
+| < 3   | :x:                |
+
+## Reporting a Vulnerability
+
+If you have found a vulnerability, please use the default GitHub feature
+https://github.com/ChristianGalla/AutoStartConfirm/security/advisories/new
+for secure communication.
+
+This is a private, open source, non-profit side project of only one maintainer.
+
+I try to respond as soon as possible (usually in a few days),
+but for example if I am busy or on vacation it could take up to a few weeks until a vulnerability is closed.