Upgrade fails from 20.04 to 20.10 because of ubunt-minimal not found in repositories

[J.]

Upgrade from 20.04 to 20.10 fails because ubunt-minimal is not found in repositories

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubuntu-release-upgrader-core 1:20.04.25
ProcVersionSignature: Ubuntu 5.4.0-52.57-generic 5.4.65
Uname: Linux 5.4.0-52-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.10
Architecture: amd64
CasperMD5CheckResult: skip
CrashDB: ubuntu
Date: Fri Oct 23 19:55:17 2020
InstallationDate: Installed on 2018-06-01 (875 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to focal on 2020-10-23 (0 days ago)
VarLogDistupgradeAptlog:
 Log time: 2020-10-23 19:54:36.546101
 Log time: 2020-10-23 19:54:43.750375
 Log time: 2020-10-23 19:55:01.280698
 Log time: 2020-10-23 19:55:19.572483
VarLogDistupgradeTermlog:

mtime.conffile..etc.update-manager.release-upgrades: 2020-05-08T22:44:46.710827

[Brian Murray (brian-murray)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 1813354, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.