Bump version to v3.4.0

Release the stand-off metadata feature for Krill output.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Change-Id: Ib381133798349eaafab4aed5340dbd2503abb1c8
diff --git a/build.gradle b/build.gradle
index 5dff3d2..6ebe5dd 100644
--- a/build.gradle
+++ b/build.gradle
@@ -5,4 +5,4 @@
 }
 
 // Zentrale Projektversion für korapxmltool
-version = '3.3.3'
+version = '3.4.0'