When I built it on 3.7.2 and 3.8.0, I have not installed devscripts. As a result the part ~ubuntu1804+1 was missing from the name of package. It was only dump1090-fa_3.8.0_amd64.deb.
It has been taken care of in the new howto for 3.8.1 (which includes installation of devscripts) which I have posted about 15 minutes ago.
How to Install Dump1090-fa & Piaware v 3.8.1 on Ubuntu 18.04 (Bionic) & Ubuntu 19.04 (Disco) amd64