Update cssutils to 2.11.1

[pyup-bot]

This PR updates cssutils from 2.7.1 to 2.11.1.

Changelog

2.11.1

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Bugfixes
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- Consolidated license to simply LGPL 3. (52)

2.11.0

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Features
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- Reduced cyclomatic complexity in selector module. (47)

2.10.3

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Bugfixes
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- Fixed DeprecationWarning with cgi module.

2.10.2

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Bugfixes
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- Remove optional dependency only required on unsupported Python versions. (48)

2.10.1

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Bugfixes
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- Replace xunit-style setup with pytest fixtures. (45)

2.10.0

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Features
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- getPropertyValue now allows specifying a default value. (42)

2.9.0

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Features
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- Made URL fetcher lenient to missing metadata.

2.8.0

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Features
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- Require Python 3.8 or later.


Bugfixes
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- Made some unreachable tests reachable.

Links

• PyPI: https://pypi.org/project/cssutils
• Changelog: https://data.safetycli.com/changelogs/cssutils/
• Docs: https://pythonhosted.org/cssutils/