docs: use private vulnerability reporting

Author: thebuilder

SECURITY.md

@@ -2,7 +2,8 @@
 
 ## Reporting a Vulnerability
 
-If you discover a security vulnerability within the `react-intersection-observer` package or have any security concerns, 
-please [create a new issue](https://github.com/thebuilder/react-intersection-observer/issues?q=sort%3Aupdated-desc+is%3Aissue+is%3Aopen) on the Github repository. 
+If you discover a security vulnerability within the `react-intersection-observer` package or have any security concerns,
+please [submit a private vulnerability report](https://github.com/thebuilder/react-intersection-observer/security/advisories/new).
+Do not open a public issue for an undisclosed vulnerability.
 
 We appreciate your responsible disclosure.