docs/security: link the JSON format we use

Author: bagder

docs/_security.html

@@ -91,5 +91,9 @@
  Each vulnerability is also provided as a single JSON that you can access at
  "https://curl.se/docs/$CVE.json" - replace $CVE with the actual curl CVE Id.
 
+<p>
+ The JSON output follows the <a href="https://ossf.github.io/osv-schema/">Open
+ Source Vulnerability format</a>
+ 
 #include "_footer.html"
 </body> </html>