DEP8 test builds uninstallable package most of the time

The DEP8 tests for sbuild in Ubuntu will attempt to build procenv for the development version of ubuntu, and then try to install the resulting package on the host, outside the chroot:

...
# We should probably only attempt to install and run procenv if the release of
# the build chroot is equal to the host, but lets be brave and try anyway
if true
#if [ "$release" = "$host_release" ]
then
    echo "INFO: Installing package '$pkg' from '$deb'"
...

This is prone to break. particularly for future SRUs, and of course existing ones where it's failing already. In bionic for example, it's failing in i386 everywhere like this:
The following packages have unmet dependencies:
 procenv : Depends: libc6 (>= 2.28) but 2.27-3ubuntu1 is to be installed
E: Unable to correct problems, you have held broken packages.

libc 2.28 is from disco.

Check also this ubuntu-devel@ short thread at https://lists.ubuntu.com/archives/ubuntu-devel/2018-November/040550.html