Fixed small typo in update.sh

update.sh

@@ -876,7 +876,7 @@ if grep -q 'SYSCTL_IPV6_DISABLED=1' mailcow.conf; then
   echo '!! IMPORTANT !!'
   echo
   echo 'SYSCTL_IPV6_DISABLED was removed due to complications. IPv6 can be disabled by editing "docker-compose.yml" and setting "enable_ipv6: true" to "enable_ipv6: false".'
-  echo 'This setting will only be active after a complete shutdown of mailcow by running $COMPOSE_COMMAND down followed by $COMPOSE_COMMAND up -d".'
+  echo "This setting will only be active after a complete shutdown of mailcow by running $COMPOSE_COMMAND down followed by $COMPOSE_COMMAND up -d."
   echo
   echo '!! IMPORTANT !!'
   echo