Bump css-parser from 1.0.5 to 1.0.6

Bumps [css-parser](https://github.com/ebook-utils/css-parser) from 1.0.5 to 1.0.6.
- [Release notes](https://github.com/ebook-utils/css-parser/releases)
- [Commits](ebook-utils/css-parser@v1.0.5...v1.0.6)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

requirements.txt

@@ -3,7 +3,7 @@ attrs>=20.2.0
 click==7.1.2
 configconfig>=0.3.0
 consolekit>=0.1.2
-css-parser==1.0.5
+css-parser==1.0.6
 domdf-python-tools>=1.1.0
 dulwich>=0.19.16
 email_validator==1.1.1