Add sessionize link to Marcus Hellberg

Author: marcushellberg

java-champions.yml

@@ -1571,6 +1571,7 @@ members:
       linkedin: https://www.linkedin.com/in/marcushellberg
       bluesky: https://bsky.app/profile/marcushellberg.dev
       github: https://github.com/marcushellberg
+      sessionize: https://sessionize.com/marcushellberg 
     avatar: img/avatars/marcushellberg.png
   - name: César Hernández
     year: 2016