That’s always been a quirk of PHP: every time you first install PHP on any system, the first thing you need to do is edit the php.ini files and set the “date.timezone” value manually. In your case, just edit both /etc/php/7.0/fpm/php.ini and /etc/php/7.0/cli/php.ini, uncomment the “date.timezone” line, and change its value to “Europe/Moscow”:
date.timezone = Europe/Moscow
And keep in mind that you will also have to do that manual edit of the php.ini files when you install versions 7.1, 7.2, 7.3, and so forth.
Thats why it is always a good practice to set default timezone inside your PHP application wherever possible, so that you don’t reply on server’s timezone.