Change docker-compose version to 3.5

This adds compatibility with older Docker installations.

Change-Id: Ibfdf866ce88eef46f3b68fce18ed6b12cfe1886a
diff --git a/cmd/hichipbridge/docker-compose.yml b/cmd/hichipbridge/docker-compose.yml
index d538fff..16a0104 100644
--- a/cmd/hichipbridge/docker-compose.yml
+++ b/cmd/hichipbridge/docker-compose.yml
@@ -1,4 +1,4 @@
-version: "3.8"
+version: "3.5"
 services:
   bridge:
     image: "avm99963/hichipbridge:latest"