Невозможно выполнить обновление с 18.04 до 20.04 - «Неофициальные программные пакеты, не предоставляемые Ubuntu ...»

При запуске sudo do-release-upgrade обнаруживается ошибка:

An unresolvable problem occurred while calculating the upgrade. 

This was likely caused by: 
* Unofficial software packages not provided by Ubuntu 
Please use the tool 'ppa-purge' from the ppa-purge 
package to remove software from a Launchpad PPA and 
try the upgrade again. 

If none of this applies, then please report this bug using the 
command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal. If 
you want to investigate this yourself the log files in 
'/var/log/dist-upgrade' will contain details about the upgrade. 
Specifically, look at 'main.log' and 'apt.log'. 


Restoring original system state

Aborting
Reading package lists... Done    
Building dependency tree          
Reading state information... Done

Я прикрепляю apt.log и main. бревно https://gist.github.com/omerbn/6e44593d8cab464be7f959b426d1c31c

Что мне делать дальше?

Спасибо,

O