The fio-3.6-2.fc29 RPM requires both Python 2 and Python 3:
$ dnf repoquery --repo=rawhide --requires fio | grep python
Except in very special circumstances, there is no need for one package
to drag in both Python stacks. Usually, this is a packaging error.
There are three executables in the fio package with `/usr/bin/python2.7`
shebang, which introduce the Python 2 dependency:
# grep -r /usr/bin/python2 .
Please remove the stray dependencies.
There is a section on shebangs in the Python RPM Porting Guide 
which covers this issue.
It's ok to do this in Rawhide only, however, it would be greatly
appreciated if you could push it to Fedora 28 as well.
If anything is unclear, or if you need any kind of assistance, you can
ask on IRC (#fedora-python on Freenode), or reply here. We'll be happy
to help investigating or fixing this issue!
This was a mistake, I intended to patch the shebang to python3; let me see what happened.
fixed in rawhide.