Add pipenv shell to before_script

2 jobs from feature/ci_flake8 in 58 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Lint
failed #1069
flake8

00:58

 
  Test
skipped #1070
test
 
Lint flake8
    pypi_mirror=state.pypi_mirror,
File "/usr/local/lib/python3.6/site-packages/pipenv/core.py", line 2184, in do_shell
shell.fork_compat(*fork_args)
File "/usr/local/lib/python3.6/site-packages/pipenv/shells.py", line 121, in fork_compat
c.interact(escape_character=None)
File "/usr/local/lib/python3.6/site-packages/pipenv/vendor/pexpect/pty_spawn.py", line 761, in interact
mode = tty.tcgetattr(self.STDIN_FILENO)
termios.error: (25, 'Inappropriate ioctl for device')
ERROR: Job failed: exit code 1