Update tinycss2 to 1.5.1

[pyup-bot]

This PR updates tinycss2 from 1.1.1 to 1.5.1.

Changelog

1.5.1

- Include parsing tests in source tarball

1.5.0

- Support most of CSS Color Level 5
- Fix tokenizer crash on escaped Dimension units and Function names

1.4.0

* Support CSS Color Level 4

1.3.0

* Support CSS nesting
* Deprecate parse_declaration_list, use parse_blocks_contents instead

1.2.1

* Fix tests included in the source tarball

1.2.0

* Drop support of Python 3.6
* Fix serialization of nested functions with no parameters
* Don’t use pytest plugins by default

Links

• PyPI: https://pypi.org/project/tinycss2
• Changelog: https://data.safetycli.com/changelogs/tinycss2/

[pyup-bot]

Closing this in favor of #1087