Update virtualenv to 16.7.7

[pyup-bot]

This PR updates virtualenv from 16.7.6 to 16.7.7.

Changelog

16.7.7

--------------------

Bugfixes
^^^^^^^^

- * fix virtualenv creation when ``--no-pip`` argument used. (`1430 <https://github.com/pypa/virtualenv/issues/1430>`_)
- upgrade bundled pip from ``19.3`` to ``19.3.1`` (`1433 <https://github.com/pypa/virtualenv/issues/1433>`_)

Links

• PyPI: https://pypi.org/project/virtualenv
• Changelog: https://pyup.io/changelogs/virtualenv/
• Homepage: https://virtualenv.pypa.io/

[codecov-io]

Codecov Report

Merging #45 into develop will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop      #45   +/-   ##
========================================
  Coverage    96.65%   96.65%           
========================================
  Files            5        5           
  Lines          269      269           
========================================
  Hits           260      260           
  Misses           9        9

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 48b6964...ec52e74. Read the comment docs.