fix(examples): volumes must match (with-nginx-proxy-postgres-fpm)

Signed-off-by: Josh <josh.t.richards@gmail.com>

.examples/docker-compose/with-nginx-proxy/postgres/fpm/compose.yaml

@@ -18,6 +18,7 @@ services:
     restart: always
     volumes:
       - nextcloud:/var/www/html:z
+      # NOTE: The `volumes` config of the `cron` and `app` containers must match
     environment:
       - POSTGRES_HOST=db
       - REDIS_HOST=redis
@@ -33,6 +34,7 @@ services:
     restart: always
     volumes:
       - nextcloud:/var/www/html:z,ro
+      # NOTE: The `volumes` included here should match those of the `app` container (unless you know what you're doing)
     environment:
       - VIRTUAL_HOST=
       - LETSENCRYPT_HOST=
@@ -48,6 +50,7 @@ services:
     restart: always
     volumes:
       - nextcloud:/var/www/html:z
+      # NOTE: The `volumes` config of the `cron` and `app` containers must match
     entrypoint: /cron.sh
     depends_on:
       - db