Fixed Jackson related security issue

Change-Id: I2053c14837683e419be705814631a3ffaad8a486
diff --git a/Changes b/Changes
index f8944ae..4dff93c 100644
--- a/Changes
+++ b/Changes
@@ -1,3 +1,7 @@
+0.31 2018-10-22
+    - [bugfix] Security upgrade of Jackson for CVE-2017-17485 and
+      CVE-2018-7489 (diewald)
+
 0.30 2018-07-31
     - Introduced docGroupRef and added VC reference in collection query (margaretha)
     - Fixed checking error in QuerySerializer (margaretha)