Update to Java 21

Change-Id: Icb040ee1c8c90abce44c5884d97a2c1a0b082ff8
Reviewed-on: https://korap.ids-mannheim.de/gerrit/c/KorAP/Koral/+/10084
Reviewed-by: margaretha <margaretha@ids-mannheim.de>
Reviewed-by: Nils Diewald <nils@diewald-online.de>
Reviewed-by: Marc Kupietz <kupietz@ids-mannheim.de>
diff --git a/Changes b/Changes
index f79eb55..07571a5 100644
--- a/Changes
+++ b/Changes
@@ -1,3 +1,6 @@
+0.48 2025-11-17
+     - [security] Update to Java 21.
+
 0.47 2025-10-16
 	- [enhancement] Add apiVersion for QuerySerializer, CorpusQuery-, 
 	  Poliqarp- and CQP processors.