Ignore macOS .DS_Store files

Change-Id: I6907b879c30885ce15d311d3d306c6e18741c45d
Signed-off-by: Matthias Becker <ma.becker@sap.com>
diff --git a/.gitignore b/.gitignore
index e809017..042a554 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,3 +11,4 @@
 
 # maven
 /*/target/
+.DS_Store