Compose: Remove the vesion field.

Newer versions of Compose don't need it and show a warning when it's
present.

Compose/matrix/docker-compose.yaml

 ---
-version: '3.5'
-
 services:
   cron:
     build:

Compose/web-proxy/host01/docker-compose.yml

 ---
-version: '3.5'
 services:
   proxy:
     build:

Compose/web-proxy/kodi/docker-compose.yml

 ---
-version: '3.5'
 services:
   proxy:
     build:

Compose/web-proxy/ns4/docker-compose.yml

 ---
-version: '3.5'
 services:
   proxy:
     build: