Comment 49 for bug 2020530

One more time for focal. The ubuntu-dev-tools SRU has already been released, so manually downloading the previous version:

$ wget https://launchpad.net/ubuntu/+source/ubuntu-dev-tools/0.176ubuntu20.04.1/+build/22596246/+files/ubuntu-dev-tools_0.176ubuntu20.04.1_all.deb
$ wget https://launchpad.net/ubuntu/+source/ubuntu-dev-tools/0.176ubuntu20.04.1/+build/22596246/+files/python3-ubuntutools_0.176ubuntu20.04.1_all.deb
$ sudo apt install ./python3-ubuntutools_0.176ubuntu20.04.1_all.deb ./ubuntu-dev-tools_0.176ubuntu20.04.1_all.deb
$ sg sbuild -c 'mk-sbuild --skip-proposed mantic'
Specified release (mantic) not known to debootstrap
$
# enable proposed
$ sudo apt install debootstrap
-> correctly pulls in new ubuntu-dev-tools as well due to breaks
$ sg sbuild -c 'mk-sbuild --skip-proposed mantic'
-> succeeds
$