Create SECURITY.md

SECURITY.md

+# Security Policy
+
+## Supported Versions
+
+Use this section to tell people about which versions of your project are
+currently being supported with security updates.
+
+| Version | Supported          |
+| ------- | ------------------ |
+| 1.8.x   | :white_check_mark: |
+| < 1.8   | :x:                |
+
+## Reporting a Vulnerability
+
+Please report security issues to linlinjavaer@gmail.com