Update SECURITY.md (#12485)

Added link to CVE list

Author: gregw

SECURITY.md

@@ -40,6 +40,6 @@ The following checklist is used to handle security issues:
 - [ ] Edit VERSION.txt and so that the CVE number is now recorded against merged PR.
 - [ ] Edit the release(s) on Github to identify CVE number that was addressed/resolved.
 - [ ] Update downstream images (Docker, etc.).
-- [ ] Update project website with new security entry.
+- [ ] Update project [website](https://jetty.org/security.html) with new security entry.
 - [ ] Review security processes & completion.