compose: add image tag to compose files

docker-compose.yml

@@ -3,7 +3,7 @@ version: '3'
 services:
     # Frontend
     web:
-        image: jitsi/web
+        image: jitsi/web:latest
         restart: ${RESTART_POLICY}
         ports:
             - '${HTTP_PORT}:80'
@@ -45,7 +45,7 @@ services:
 
     # XMPP server
     prosody:
-        image: jitsi/prosody
+        image: jitsi/prosody:latest
         restart: ${RESTART_POLICY}
         expose:
             - '5222'
@@ -110,7 +110,7 @@ services:
 
     # Focus component
     jicofo:
-        image: jitsi/jicofo
+        image: jitsi/jicofo:latest
         restart: ${RESTART_POLICY}
         volumes:
             - ${CONFIG}/jicofo:/config:Z
@@ -137,7 +137,7 @@ services:
 
     # Video bridge
     jvb:
-        image: jitsi/jvb
+        image: jitsi/jvb:latest
         restart: ${RESTART_POLICY}
         ports:
             - '${JVB_PORT}:${JVB_PORT}/udp'