wireguard-tools: 0.0.20190913 -> 0.0.20191012

https://lists.zx2c4.com/pipermail/wireguard/2019-October/004594.html

Also decided to add myself to the maintainers list as I use WireGuard
pretty heavily for private/work-related stuff and I intend to help taking care
of the WireGuard ecosystem in NixOS as well.