chore: add security.md (#189)

## Description

add security.md

## Related Issue

Fixes #
<!-- or -->
Relates to #

## Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [x] Other (security config, docs update, etc)

## Checklist before merging

- [ ] Test, docs, adr added or updated as needed
- [ ] [Contributor Guide
Steps](https://github.com/defenseunicorns/uds-template-capability/blob/main/CONTRIBUTING.md)(https://github.com/defenseunicorns/uds-template-capability/blob/main/CONTRIBUTING.md#submitting-a-pull-request)
followed

SECURITY.md

+# Security Policy
+
+## Supported Versions
+
+As [UDS Core](https://github.com/defenseunicorns/uds-core) has not yet reached v1.0.0, only the current latest minor release is supported.
+
+## Reporting a Vulnerability
+
+Please email `security-notice [at] defenseunicorns.com` to report a vulnerability. If you are unable to disclose details via email, please let us know and we can coordinate alternate communications.