Update mailmap

Change-Id: I0f02518edc03c281faada576dc6ae53f4dc20d7e
diff --git a/.mailmap b/.mailmap
index 2d44453..cc103a4 100644
--- a/.mailmap
+++ b/.mailmap
@@ -1 +1,2 @@
+Matthias Sohn <matthias.sohn@sap.com> <matthias.sohn@gmail.com>
 Thomas Draebing <thomas.draebing@sap.com>