Bump to v3.1.1

Change-Id: Ic5a1a572e550a8ae1924a4afd1d44932bb56fe49
diff --git a/build.gradle b/build.gradle
index e3dea96..1aa733d 100644
--- a/build.gradle
+++ b/build.gradle
@@ -5,4 +5,4 @@
 }
 
 // Zentrale Projektversion für korapxmltool
-version = '3.1.0'
+version = '3.1.1'