Update readme with the link to the latest security audit

Closes #6809.
[skip ci]

Signed-off-by: Neil Twigg <[email protected]>

Author: neilalexander

README.md

@@ -63,7 +63,7 @@ Who uses NATS? See our [list of users](https://nats.io/#who-uses-nats) on [https
 
 ### Security Audit
 
-A third party security audit was performed by Cure53, you can see the full report [here](https://github.com/nats-io/nats-general/blob/main/reports/Cure53_NATS_Audit.pdf).
+A third party security audit was performed by Trail of Bits following engagement by the Open Source Technology Improvement Fund (OSTIF). You can see the [full report from April 2025 here](https://github.com/trailofbits/publications/blob/master/reviews/2025-04-ostif-nats-securityreview.pdf).
 
 ### Reporting Security Vulnerabilities