Description of problem:
package file conflict of python3-traitsui blocks Fedora upgrade from 32 to 34.

Version-Release number of selected component (if applicable):
7.1.1-2

How reproducible:
100%

Steps to Reproduce:
1. on a Fedora 32 computer run as root in terminal:
# dnf install -y python3-traitsui
# dnf update -y --refresh && reboot
2. continue as root in terminal:
# dnf install -y dnf-plugin-system-upgrade
# dnf system-upgrade download -y --releasever=34

Actual results:
...
<packages downloaded>
Running transaction check
Transaction check succeeded.
Running transaction test
The downloaded packages were saved in cache until the next successful transaction.
You can remove cached packages by executing 'dnf clean packages'.
Error: Transaction test error:
  file /usr/share/doc/python3-traitsui/examples/demo from install of python3-traitsui-7.1.1-2.fc34.noarch conflicts with file from package python3-traitsui-6.1.3-2.fc32.noarch


Expected results:
...
<packages downloaded>
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.

so this will work:
# dnf system-upgrade reboot

Additional info:
uninstall python3-traitsui to unblock upgrade