Remove version from docker-compose.yml [deprecated] (#9)

Author: quintenvandamme

docs/self-hosting/installation/index.md

@@ -65,8 +65,6 @@ The downloaded `docker-compose.yml` file should contain the template below with
 :::
 
 ```yaml title="docmost/docker-compose.yml"
-version: "3"
-
 services:
   docmost:
     image: docmost/docmost:latest