C++ and GLib (C) Packages for Ubunutu Instructions are wrong

[Michiel Van der Lee]

The instructions found here https://arrow.apache.org/install/ don't work.
The /etc/apt/sources.list.d/red-data-tools.list file points to the 'main'
component. The 'main' component only exists for Debian, for Ubuntu it
should be 'universe'.
Seen here: https://packages.red-data-tools.org/ubuntu/dists/bionic/universe