chore: add security guidelines

SECURITY.md

@@ -0,0 +1,9 @@
+# Security policy
+
+## Reporting a Vulnerability
+
+Please report any suspected security vulnerabilities [here][new-advisory]. If the issue is confirmed, we will release a
+patch as soon as possible depending on complexity. Please follow [responsible disclosure
+practices](https://en.wikipedia.org/wiki/Coordinated_vulnerability_disclosure). Thanks!
+
+[new-advisory]: https://github.com/mehalter/astromason-registry/security/advisories/new