Add Security Policy

Author: mike-oakley

SECURITY.md

@@ -0,0 +1,13 @@
+# Security Policy
+
+## Supported Versions
+
+As we're a small project and have limited maintainer capacity, only the latest major version of OpenAPI Pydantic is actively maintained. Whilst
+we are pre-v1, this extends to the latest minor version - so only the latest 0.x version is actively maintained. Please update to the latest available
+version before reporting bugs or security vulnerabilities.
+
+## Reporting a Vulnerability
+
+To report a vulnerability associated with this project, use the [GitHub vulnerability reporting tool](https://docs.github.com/en/code-security/security-advisories/guidance-on-reporting-and-writing-information-about-vulnerabilities/privately-reporting-a-security-vulnerability).
+Head over to the [Security](https://github.com/mike-oakley/openapi-pydantic/security) tab
+and click **Report a vulnerability** to open the advisory form.