Bump wemake-python-styleguide from 0.8.1 to 0.9.0 (#103)

Bumps [wemake-python-styleguide](https://github.com/wemake-services/wemake-python-styleguide) from 0.8.1 to 0.9.0.
- [Release notes](https://github.com/wemake-services/wemake-python-styleguide/releases)
- [Changelog](https://github.com/wemake-services/wemake-python-styleguide/blob/master/CHANGELOG.md)
- [Commits](wemake-services/wemake-python-styleguide@0.8.1...0.9.0)

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

Author: dependabot-preview[bot]

poetry.lock

@@ -37,7 +37,7 @@ typing-extensions = "^3.7"
 
 [tool.poetry.dev-dependencies]
 mypy = "^0.701"
-wemake-python-styleguide = "^0.8.1"
+wemake-python-styleguide = "^0.9.0"
 flake8-pytest = "^1.3"
 
 safety = "^1.8"