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          |
+| -------- | ------------------ |
+| 3.5.99.x | :white_check_mark: |
+| 3.6.x    | :x:                |
+
+## Reporting a Vulnerability
+
+Use this section to tell people how to report a vulnerability.
+
+Tell them where to go, how often they can expect to get an update on a
+reported vulnerability, what to expect if the vulnerability is accepted or
+declined, etc.