Update pregel-bootstrap GDS and Neo4j

Co-Authored-By: Ioannis Panagiotas <ioannis.panagiotas@neo4j.com>

Author: vnickolov

examples/pregel-bootstrap/build.gradle

@@ -7,8 +7,8 @@ plugins {
 
 ext {
     // Make sure these are the same as your installation of GDS and Neo4j
-    gdsVersion = '2.18.0'
-    neo4jVersion = '2025.05.0'
+    gdsVersion = '2.19.0'
+    neo4jVersion = '2025.06.0'
 
     // Necessary to generate value classes for Pregel configs
     immutablesVersion = '2.10.1'