Update pip to 9.0.1

[pyup-bot]

There's a new version of pip available.
You are currently using 8.1.2. I have updated it to 9.0.1

These links might come in handy: PyPI | Changelog | Homepage

Changelog

9.0.1

• Correct the deprecation message when not specifying a --format so that it
  uses the correct setting name (format) rather than the incorrect one
  (list_format) (:issue:4058).

• Fix pip check to check all available distributions and not just the
  local ones (:issue:4083).

• Fix a crash on non ASCII characters from lsb_release (:issue:4062).

• Fix an SyntaxError in an an used module of a vendored dependency
  (:issue:4059).

• Fix UNC paths on Windows (:issue:4064).

9.0.0

• BACKWARD INCOMPATIBLE Remove the attempted autodetection of requirement
  names from URLs, URLs must include a name via egg=.

• DEPRECATION pip install --egg have been deprecated and will be
  removed in the future. This "feature" has a long list of drawbacks which
  break nearly all of pip's other features in subtle and hard-to-diagnose
  ways.

• DEPRECATION --default-vcs option (:issue:4052).

• WARNING pip 9 cache can break forward compatibility with previous pip
  versions if your package repository allows chunked responses (:issue:4078).

• Add a pip check command to check installed packages dependencies
  (:pull:3750).

• Add option allowing user to abort pip operation if file/directory exists

• Add Appveyor CI

• Uninstall existing packages when performing an editable installation of
  the same packages (:issue:1548).

• pip show is less verbose by default. --verbose prints multiline fields.
  (:pull:3858).

• Add optional column formatting to pip list (:issue:3651).

• Add --not-required option to pip list, which lists packages that are
  not dependencies of other packages.

• Fix builds on systems with symlinked /tmp directory for custom
  builds such as numpy (:pull:3701).

• Fix regression in pip freeze: when there is more than one git remote,
  priority is given to the remote named origin (:pull:3708, :issue:3616).

• Fix crash when calling pip freeze with invalid requirement installed
  (:pull:3704, :issue:3681).

• Allow multiple --requirement files in pip freeze (:pull:3703).

• Implementation of pep-503 data-requires-python. When this field is
  present for a release link, pip will ignore the download when
  installing to a Python version that doesn't satisfy the requirement.

• pip wheel now works on editable packages too (it was only working on
  editable dependencies before); this allows running pip wheel on the result
  of pip freeze in presence of editable requirements (:pull:3695,
  :issue:3291).

• Load credentials from .netrc files (:pull:3715, :issue:3569).

• Add --platform, --python-version, --implementation and --abi parameters to
  pip download. These allow utilities and advanced users to gather
  distributions for interpreters other than the one pip is being run on.
  (:pull:3760)

• Skip scanning virtual environments, even when venv/bin/python is a dangling
  symlink.

• Added pip completion support for the fish shell.

• Fix problems on Windows on Python 2 when username or hostname contains
  non-ASCII characters (:issue:3463, :pull:3970, :pull:4000).

• Use git fetch --tags to fetch tags in addition to everything else that
  is normally fetched; this is necessary in case a git requirement url
  points to a tag or commit that is not on a branch (:pull:3791)

• Normalize package names before using in pip show (:issue:3976)

• Raise when Requires-Python do not match the running version and add
  --ignore-requires-python option as escape hatch (:pull:3846).

• Report the correct installed version when performing an upgrade in some
  corner cases (:issue:2382)

• Add -i shorthand for --index flag in pip search

• Do not optionally load C dependencies in requests (:issue:1840,
  :issue:2930, :issue:3024)

• Strip authentication from SVN url prior to passing it to svn
  (:pull:3697, :issue:3209).

• Also install in platlib with --target option (:pull:3694, :issue:3682).

• Restore the ability to use inline comments in requirements files passed to
  pip freeze (:issue:3680).

Got merge conflicts? Close this PR and delete the branch. I'll create a new PR for you.

Happy merging! 🤖

[pyup-bot]

Closing this in favor of #189