https://lists.ubuntu.com/archives/ubuntu-announce/2018-July/000232.html
Ubuntu 17.10 (Artful Aardvark) reaches End of Life on July 19 2018
Ubuntu announced its 17.10 (Artful Aardvark) release almost 9 months
ago, on October 19, 2017. As a non-LTS release, 17.10 has a 9-month
support cycle and, as such, the support period is now nearing its
end and Ubuntu 17.10 will reach end of life on Thursday, July 19th.
At that time, Ubuntu Security Notices will no longer include
information or updated packages for Ubuntu 17.10.
Fixes https://github.com/dotnet/core/issues/1824