Install the Russian language pack via composer is never easier.
Install Russian pack:
composer require qpard/magento2-russian-language-pack:*
php bin/magento cache:clean
php bin/magento setup:static-content:deploy ru_RU
Update Russian pack:
composer update qpard/magento2-russian-language-pack:*
php bin/magento cache:clean
php bin/magento setup:static-content:deploy ru_RU