I try to upgrade from 18.03 to 20.04 LTS version, but I only got purge message with PPA command. when i do, the error continue

[Jorge Caballero]

sudo update-manager -d
Checking for a new Ubuntu release
/usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeFetcher.py:23: PyGIWarning: Gtk was imported without specifying a version first. Use gi.require_version('Gtk', '3.0') before import to ensure that the right version gets loaded.
  from gi.repository import Gtk, Gdk
/usr/lib/python3/dist-packages/DistUpgrade/ReleaseNotesViewerWebkit.py:33: PyGIWarning: WebKit2 was imported without specifying a version first. Use gi.require_version('WebKit2', '4.0') before import to ensure that the right version gets loaded.
  from gi.repository import WebKit2 as WebKit

(do-release-upgrade:17286): IBUS-WARNING **: 12:40:33.921: The owner of /home/ares/.config/ibus/bus is not root!
Gtk-Message: 12:40:33.934: GtkDialog mapped without a transient parent. This is discouraged.

(do-release-upgrade:17286): IBUS-WARNING **: 12:40:33.941: Unable to connect to ibus: Unexpected lack of content trying to read a line
authenticate 'focal.tar.gz' against 'focal.tar.gz.gpg'
extracting 'focal.tar.gz'

(focal:17286): IBUS-WARNING **: 12:40:44.751: The owner of /home/ares/.config/ibus/bus is not root!

(focal:17286): IBUS-WARNING **: 12:40:50.358: Unable to connect to ibus: Unexpected lack of content trying to read a line
ares@valhalla:~$ ppa-purge

Command 'ppa-purge' not found, but can be installed with:

sudo apt install ppa-purge

##################################
result: could not calculate the upgrade. an unresolvable problem occurred while calculate the upgrade ...

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubuntu-release-upgrader-core 1:18.04.37
ProcVersionSignature: Ubuntu 5.3.0-61.55~18.04.1-generic 5.3.18
Uname: Linux 5.3.0-61-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.15
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: ubuntu:GNOME
Date: Tue Jun 30 13:36:14 2020
InstallationDate: Installed on 2019-08-13 (321 days ago)
InstallationMedia: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to bionic on 2020-06-30 (0 days ago)
VarLogDistupgradeTermlog:

[Brian Murray (brian-murray)]

Reviewing the files from your upgrade attempt you seem to have enabled a PPA that provides Xorg packages. This will prevent the upgrade as that PPA contains package version numbers greater than the release to which you are upgrading. You can revert the PPA by installing the ppa-purge package from the official Ubuntu archive and then running 'sudo ppa-purge ppa:oibaf/graphics-drivers'. After that you can try upgrading again and if it still fails open a new bug report. Thanks and good luck!