Revise security information and reporting guidelines

Updated security contact information and support details.

Author: pboling

SECURITY.md

@@ -0,0 +1,24 @@
+# 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          |
+| ------- | ------------------ |
+| 0.0.x   | :white_check_mark: |
+
+## Security contact information
+
+To report a security vulnerability, please use the
+[Tidelift security contact](https://tidelift.com/security).
+Tidelift will coordinate the fix and disclosure.
+
+## Additional Support
+
+If you are interested in support for versions older than the latest release,
+please consider sponsoring the project / maintainer @ https://liberapay.com/pboling/donate,
+or find other sponsorship links in the [README].
+
+[README]: README.md