Description of problem:
SSIA, I assume "py3-virtualenv" is just "virtualenv" meanwhile, this needs to be adjusted in Fedora 29+.

Version-Release number of selected component (if applicable):
pipsi-0.9-9.fc29.noarch

How reproducible:
reproducible

Steps to Reproduce:
1. pipsi install pew

Actual results:
nils@gibraltar:~> pipsi install pew
Traceback (most recent call last):
  File "/usr/bin/pipsi", line 11, in <module>
    load_entry_point('pipsi==0.9', 'console_scripts', 'pipsi')()
  File "/usr/lib/python3.7/site-packages/click/core.py", line 721, in __call__
    return self.main(*args, **kwargs)
  File "/usr/lib/python3.7/site-packages/click/core.py", line 696, in main
    rv = self.invoke(ctx)
  File "/usr/lib/python3.7/site-packages/click/core.py", line 1065, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/lib/python3.7/site-packages/click/core.py", line 894, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/lib/python3.7/site-packages/click/core.py", line 534, in invoke
    return callback(*args, **kwargs)
  File "/usr/lib/python3.7/site-packages/click/decorators.py", line 27, in new_func
    return f(get_current_context().obj, *args, **kwargs)
  File "/usr/lib/python3.7/site-packages/pipsi.py", line 366, in install
    if repo.install(package, python, editable):
  File "/usr/lib/python3.7/site-packages/pipsi.py", line 236, in install
    if Popen(args).wait() != 0:
  File "/usr/lib64/python3.7/subprocess.py", line 756, in __init__
    restore_signals, start_new_session)
  File "/usr/lib64/python3.7/subprocess.py", line 1499, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: 'py3-virtualenv': 'py3-virtualenv'
nils@gibraltar:~>

Expected results:
Installs pew.


Additional info: