Update the version to 2026.06 (#356)

Author: renetapopova

antora.yml

@@ -1,14 +1,14 @@
 name: java-reference
 title: Java Reference
-version: '2026.05'
+version: '2026.06'
 start_page: ROOT:index.adoc
 nav:
 - modules/ROOT/content-nav.adoc
 asciidoc:
   attributes:
-    neo4j-version: '2026.05'
-    neo4j-version-exact: '2026.05.0'
-    neo4j-buildnumber: '2026.05'
+    neo4j-version: '2026.06'
+    neo4j-version-exact: '2026.06.0'
+    neo4j-buildnumber: '2026.06'
     java-driver-version: '6.0.5'
     neo4j-documentation-branch: 'dev'
     page-origin-private: false