dephell convert conflict with a PEP440 direct reference

[graingert]

Short description

I have a direct reference in my setup.cfg and I'd like to make a requirements.lock
https://github.com/graingert/modernize/blob/8d10eedea52eece30aac0a43375603847e9f9fc2/setup.cfg#L39

Output

Steps to reproduce

$ hub clone graingert/modernize
$ git checkout 8d10eedea52eece30aac0a43375603847e9f9fc2
$ pipx run dephell convert -- --from=setup.py --to=requirements.lock --traceback
...

Traceback

WARNING cannot find config file 
⠙ layers: 3, mutations: 195WARNING mutations limit reached (limit=200)
WARNING conflict was found 
————————————————————————————————————————————————————————————————————————————————

coverage>=3.7.1

 + * goes from modernize==0.7
 + >=3.7.1 goes from pytest-cov==2.10.1

Releases:
 + 1.0

Locked nodes:
 + fissix==20.8.0
 + sphinx==3.2.1
 + pytest-cov==2.10.1
 + coveralls==1.8.0

Nodes with constraints:
 + fissix
 + sphinx==3.*,>=3.2.0
 + pytest
 + pytest-cov
 + coveralls
 + coverage
 + appdirs
 + sphinxcontrib-applehelp
 + sphinxcontrib-devhelp
 + sphinxcontrib-jsmath
 + sphinxcontrib-htmlhelp
 + sphinxcontrib-serializinghtml
 + sphinxcontrib-qthelp
 + jinja2>=2.3
 + pygments>=2.0
 + docutils>=0.12
 + snowballstemmer>=1.1
 + babel>=1.3
 + alabaster<0.8,>=0.7
 + imagesize
 + requests>=2.5.0
 + setuptools
 + packaging
 + colorama>=0.3.5

Free nodes:

Tried 200 mutations.

Config

no config

Versions

WARNING cannot find config file 
WARNING cannot find module, trying to install (package=pygments)
Collecting pygments
Installing collected packages: pygments
Successfully installed pygments-2.6.1

{
  "cache": "11.06Mb",
  "path": "/home/graingert/.local/pipx/.cache/8c391109890bc16/lib/python3.8/site-packages/dephell",
  "python": "/home/graingert/.local/pipx/.cache/8c391109890bc16/bin/python",
  "version": "0.8.3",
  "versions": {
    "dephell-archive": "0.1.7",
    "dephell-argparse": "0.1.3",
    "dephell-changelogs": "0.0.1",
    "dephell-discover": "0.2.10",
    "dephell-licenses": "0.1.7",
    "dephell-links": "0.1.5",
    "dephell-markers": "1.0.3",
    "dephell-pythons": "0.1.15",
    "dephell-setuptools": "0.2.4",
    "dephell-shells": "0.1.5",
    "dephell-specifier": "0.2.2",
    "dephell-venvs": "0.1.17",
    "dephell-versioning": "0.1.2"
  }
}

[graingert]

but I'd expect the version to be:

+ 5.2.2a0 goes from modernize==0.7