netselect-apt generated sources.list does not include the correct release file syntax

`Err:5 http://security.debian.org stable/updates Release
404 Not Found [IP: 146.75.78.132 80]
Reading package lists... Done
E: The repository 'http://security.debian.org stable/updates Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.`

must manually add '-security' to make it `deb http://security.debian.org/ stable-security/updates main`

Also the tool does not recognize 'bullseye' as a code name for current stable.