[5.0.x] Fixed #34990 -- Changed link to OWASP in CSRF docs.

The OWASP site is the standard resource for web application
security information.
Backport of aceee39d44994df20d13104e55ae61845d7a1e95 from main

docs/ref/csrf.txt

@@ -18,7 +18,7 @@ The first defense against CSRF attacks is to ensure that GET requests (and other
 Requests via 'unsafe' methods, such as POST, PUT, and DELETE, can then be
 protected by the steps outlined in :ref:`using-csrf`.
 
-.. _Cross Site Request Forgeries: https://www.squarefree.com/securitytips/web-developers.html#CSRF
+.. _Cross Site Request Forgeries: https://owasp.org/www-community/attacks/csrf#overview
 
 .. _how-csrf-works: