chore: change security url

SECURITY.md

@@ -6,4 +6,4 @@ Only the latest release is supported
 
 ## Reporting a Vulnerability
 
-To report a security issue, please contact convertx@emrik.org
+To report a security issue, please use the GitHub Security Advisory ["Report a Vulnerability"](https://github.com/C4illin/ConvertX/security/advisories/new) tab.