Update README with pip instructions for Fedora

[bebosudo]

I tried installing the RPM from the OpenSUSE repo with the repository home:fusion809, but there's no blockify inside.
I also tried installing directly the RPM from https://software.opensuse.org/download.html?project=home%3Afusion809&package=blockify, but the blockify program produced the following traceback:

  File "/usr/bin/blockify", line 6, in <module>
    from pkg_resources import load_entry_point
  File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 3112, in <module>
    @_call_aside
  File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 3096, in _call_aside
    f(*args, **kwargs)
  File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 3125, in _initialize_master_working_set
    working_set = WorkingSet._build_master()
  File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 578, in _build_master
    ws.require(__requires__)
  File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 895, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 781, in resolve
    raise DistributionNotFound(req, requirers)
pkg_resources.DistributionNotFound: The 'blockify==3.6.3' distribution was not found and is required by the application

Maybe some patched dependencies from the repo are required?

The pip method is the only method that installed a working version.
Tested on f29 with python 3.7.