Add workshop registration details to 2025 edition

Added workshop registration information for MediaEval 2025.

Author: cmihaigabriel

_editions/2025.md

@@ -13,6 +13,9 @@ MediaEval goes beyond other benchmarks and data science challenges in that it al
 scores to also working to achieve deeper understanding about the challenges. For example, characteristics of the data, strengths and weaknesses of particular types of approaches, and observations 
 about the evaluation procedure.
 
+##### Workshop registration:
+Workshop registration is now available at [MediaEval 2025 Workshop registration](www.eventbrite.ie/e/mediaeval-2025-tickets-1427931193639)
+
 ##### Registration:
 Signup for MediaEval 2025 is now open via the [MediaEval 2025 registration form](https://forms.gle/y7v1VLP7D9vsbuqv5).