Readd version for correct dependencies

Change-Id: Icf04711d526e0693952c78879693a2f5eec7e5de
diff --git a/compose.yaml b/compose.yaml
index 7a6e182..bb7c87c 100644
--- a/compose.yaml
+++ b/compose.yaml
@@ -1,3 +1,4 @@
+version: '3.9'
 volumes:
   example-index:
 services: