Upstream changes
- Set user related sessions for single user mode
- Merge pull request 'Fix PHP8 empty param warning' (#79) from powerivq/tt-rss:php8compat into master
- Merge pull request 'Add last_login_update session to single user mode' (#80) from powerivq/tt-rss:last_login into master
- Add last_login to single user mode
- Fix PHP8 empty param problem