Add links for security issues (valkey-io#299)

Add an initial security release page. In the fullness of time I would
like to also include our version support here, but until that has been
decided I would like to keep this simple and just include links.

---------

Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>

SECURITY.md

@@ -1,8 +1,6 @@
-# Security Policy
-
-Valkey is under development, more information will become available.
-
 ## Reporting a Vulnerability
 
-If you believe you've discovered a serious vulnerability, please contact Madelyn
-at placeholderkv@gmail.com
+If you believe you've discovered a security vulnerability, please contact the Valkey team at security@lists.valkey.io.
+Please *DO NOT* create an issue.
+We follow a responsible disclore procedure, so depending on the severity of the issue we may notify Valkey vendors about the issue before releasing it publicly.
+If you would like to be added to our list of vendors, please reach out to the Valkey team at maintainers@lists.valkey.io.