Update whitenoise to 4.1.3

[pyup-bot]

This PR updates whitenoise from 4.1 to 4.1.3.

Changelog

4.1.3

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* Fix handling of zero-valued mtimes which can occur when running on some
filesystems (thanks `twosigmajab <https://github.com/twosigmajab>`_ for
reporting).
* Fix potential path traversal attack while running in autorefresh mode on
Windows (thanks `phith0n <https://github.com/phith0n>`_ for reporting).
This is a good time to reiterate that autofresh mode is never intended for
production use.

4.1.2

------

* Add correct MIME type for WebAssembly, which is required for files to be
executed (thanks `mdboom <https://github.com/mdboom>`_ ).
* Stop accessing the FILE_CHARSET Django setting which was almost entirely
unused and is now deprecated (thanks `timgraham
<https://github.com/timgraham>`_).

4.1.1

------

* Fix `bug <https://github.com/evansd/whitenoise/issues/202>`_ in ETag
handling (thanks `edmorley <https://github.com/edmorley>`_).
* Documentation fixes (thanks `jamesbeith <https://github.com/jamesbeith>`_
and `mathieusteele <https://github.com/mathieusteele>`_).

Links

• PyPI: https://pypi.org/project/whitenoise
• Changelog: https://pyup.io/changelogs/whitenoise/
• Homepage: http://whitenoise.evans.io

[coveralls]

Pull Request Test Coverage Report for Build 985

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 73.896%

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Totals
Change from base Build 877:	0.0%
Covered Lines:	1840
Relevant Lines:	2490

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💛 - Coveralls

[pyup-bot]

Closing this in favor of #270