chore(docker-compose): fix EDITION var warnings (#363)

Because

- warnings on `make` for `EDITION`

This commit

- add a default value (empty string)

```
 !  ~/w/i/vdp   main …  make stop
WARN[0000] The "EDITION" variable is not set. Defaulting to a blank string. 
WARN[0000] The "EDITION" variable is not set. Defaulting to a blank string. 
WARN[0000] The "EDITION" variable is not set. Defaulting to a blank string. 
WARN[0000] The "EDITION" variable is not set. Defaulting to a blank string. 
[+] Stopping 5/5
 ✔ Container pipeline-backend-worker  Stopped                                                                                                                                                                                                                                                                                                                                                                                                                                              0.5s 
 ✔ Container connector-backend        Stopped                                                                                                                                                                                                                                                                                                                                                                                                                                              1.5s 
 ✔ Container controller-vdp           Stopped                                                                                                                                                                                                                                                                                                                                                                                                                                              0.5s 
 ✔ Container pipeline-backend         Stopped                                                                                                                                                                                                                                                                                                                                                                                                                                              2.6s 
 ✔ Container socat                    Stopped                                                                                                                                                                                                                                                                                                                                                                                                                                              0.4s 
```

docker-compose.yml

@@ -33,7 +33,7 @@ services:
       CFG_SERVER_DEBUG: "false"
       CFG_SERVER_MAXDATASIZE: ${MAX_DATA_SIZE}
       CFG_SERVER_USAGE_ENABLED: ${USAGE_ENABLED}
-      CFG_SERVER_EDITION: ${EDITION}
+      CFG_SERVER_EDITION: ${EDITION:-}
       CFG_DATABASE_HOST: ${POSTGRESQL_HOST}
       CFG_DATABASE_PORT: ${POSTGRESQL_PORT}
       CFG_DATABASE_USERNAME: postgres
@@ -62,7 +62,7 @@ services:
       CFG_SERVER_DEBUG: "false"
       CFG_SERVER_MAXDATASIZE: ${MAX_DATA_SIZE}
       CFG_SERVER_USAGE_ENABLED: ${USAGE_ENABLED}
-      CFG_SERVER_EDITION: ${EDITION}
+      CFG_SERVER_EDITION: ${EDITION:-}
       CFG_DATABASE_HOST: ${POSTGRESQL_HOST}
       CFG_DATABASE_PORT: ${POSTGRESQL_PORT}
       CFG_DATABASE_USERNAME: postgres
@@ -121,7 +121,7 @@ services:
       CFG_SERVER_PUBLICPORT: ${CONNECTOR_BACKEND_PUBLICPORT}
       CFG_SERVER_DEBUG: "false"
       CFG_SERVER_USAGE_ENABLED: ${USAGE_ENABLED}
-      CFG_SERVER_EDITION: ${EDITION}
+      CFG_SERVER_EDITION: ${EDITION:-}
       CFG_DATABASE_HOST: ${POSTGRESQL_HOST}
       CFG_DATABASE_PORT: ${POSTGRESQL_PORT}
       CFG_DATABASE_USERNAME: postgres
@@ -147,7 +147,7 @@ services:
     restart: unless-stopped
     environment:
       CFG_SERVER_DEBUG: "false"
-      CFG_SERVER_EDITION: ${EDITION}
+      CFG_SERVER_EDITION: ${EDITION:-}
       CFG_DATABASE_HOST: ${POSTGRESQL_HOST}
       CFG_DATABASE_PORT: ${POSTGRESQL_PORT}
       CFG_DATABASE_USERNAME: postgres