Pipenv install --skip-lock does not interpolate environment variables

[orf]

Issue description

When running pipenv install --skip-lock pipenv fails with a plette.models.base.ValidationError. It appears environment variables are not expanded. pipenv install works fine.

Expected result

Both pipenv install invocations should work.

Actual result

You have a traceback like so:

    self.validate(data)
  File "/usr/local/Cellar/pipenv/2018.11.26_2/libexec/lib/python3.7/site-packages/pipenv/vendor/plette/lockfiles.py", line 80, in validate
    klass.validate(data[key])
  File "/usr/local/Cellar/pipenv/2018.11.26_2/libexec/lib/python3.7/site-packages/pipenv/vendor/plette/models/sections.py", line 70, in validate
    klass.validate(data[key])
  File "/usr/local/Cellar/pipenv/2018.11.26_2/libexec/lib/python3.7/site-packages/pipenv/vendor/plette/models/base.py", line 132, in validate
    cls.item_class.validate(d)
  File "/usr/local/Cellar/pipenv/2018.11.26_2/libexec/lib/python3.7/site-packages/pipenv/vendor/plette/models/base.py", line 67, in validate
    return validate(cls, data)
  File "/usr/local/Cellar/pipenv/2018.11.26_2/libexec/lib/python3.7/site-packages/pipenv/vendor/requirementslib/models/pipfile.py", line 59, in validate
    raise plette.models.base.ValidationError(data, v)
plette.models.base.ValidationError: {'url': 'https://${CREDENTIALS}@server.com/repository/pypi/simple', 'name': 'name'}

Steps to replicate

url = "https://${CREDENTIALS}@myserver/repository/pypi/simple"
name = "name"

[packages]

[dev-packages]
pytest = "*"

[requires]
python_version = "3.7"

Run pipenv install --skip-lock

[frostming]

@orf Can you verify the issue against master branch? I can't reproduce here. Thanks

[bagrat]

That's probably because of the verify_ssl missing, which is required.

[orf]

This indeed works in master @frostming. verify_ssl has no effect