Update versions.md

Signed-off-by: Raül <raulojeda@eprosima.com>

Author: raulojeda22

versions.md

@@ -3,6 +3,7 @@ Forthcoming
 
 * ResourceLimitsQosPolicy maximum limits default values changed to LENGTH_UNLIMITED (i.e. infinite).
 * Discovery Server CLIENT participants now behave like SUPER_CLIENT participants.
+* Secure Discovery Server is now exclusively a Fast DDS Pro feature.
 
 Version v3.4.0
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