postgresql 10 for Ubuntu 17.10 artful?
I have replaced artful-pgdg with zesty-pgdg in /etc/apt/sources.list.d/pgdg.list and it worked for me

https://wiki.postgresql.org/wiki/Apt/FAQ

I am using a non-LTS release of Ubuntu

Non-LTS releases of Ubuntu are only added to the repository if the packages from the latest LTS release are incompatible with the release in question. Using the latest LTS release instead generally works, unless library dependencies cannot be fulfilled, in which case we will provide updated packages for the non-LTS release.