osc from home:CZ-NIC:knot-resolver-build project

For xUbuntu 18.04 run the following:

Keep in mind that the owner of the key may distribute updates, packages and repositories that your system will trust (more information).

echo 'deb http://download.opensuse.org/repositories/home:/CZ-NIC:/knot-resolver-build/xUbuntu_18.04/ /' | sudo tee /etc/apt/sources.list.d/home:CZ-NIC:knot-resolver-build.list
curl -fsSL https://download.opensuse.org/repositories/home:CZ-NIC:knot-resolver-build/xUbuntu_18.04/Release.key | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/home_CZ-NIC_knot-resolver-build.gpg > /dev/null
sudo apt update
sudo apt install osc