Update astroid to 2.7.1

[pyup-bot]

This PR updates astroid from 2.6.6 to 2.7.1.

Changelog

2.7.1

============================
Release date: 2021-08-16

* When processing dataclass attributes, only do typing inference on collection types.
Support for instantiating other typing types is left for the future, if desired.

Closes 1129

* Fixed LookupMixIn missing from ``astroid.node_classes``.

2.7.0

============================
Release date: 2021-08-15

* Import from ``astroid.node_classes`` and ``astroid.scoped_nodes`` has been deprecated in favor of
``astroid.nodes``. Only the imports from ``astroid.nodes`` will work in astroid 3.0.0.

* Add support for arbitrary Enum subclass hierachies

Closes PyCQA/pylint533
Closes PyCQA/pylint2224
Closes PyCQA/pylint2626

* Add inference tips for dataclass attributes, including dataclasses.field calls.
Also add support for InitVar.

Closes PyCQA/pylint2600
Closes PyCQA/pylint2698
Closes PyCQA/pylint3405
Closes PyCQA/pylint3794

* Adds a brain that deals with dynamic import of `IsolatedAsyncioTestCase` class of the `unittest` module.

Closes PyCQA/pylint4060

Links

• PyPI: https://pypi.org/project/astroid
• Changelog: https://pyup.io/changelogs/astroid/
• Repo: https://github.com/PyCQA/astroid

[codecov]

Codecov Report

Merging #95 (be570b9) into master (9307f73) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #95   +/-   ##
=======================================
  Coverage   67.85%   67.85%           
=======================================
  Files           2        2           
  Lines          56       56           
=======================================
  Hits           38       38           
  Misses         18       18           

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[pyup-bot]

Closing this in favor of #97