Bump tomlkit from 0.5.11 to 0.6.0

Bumps [tomlkit](https://github.com/sdispater/tomlkit) from 0.5.11 to 0.6.0.
- [Release notes](https://github.com/sdispater/tomlkit/releases)
- [Changelog](https://github.com/sdispater/tomlkit/blob/master/CHANGELOG.md)
- [Commits](python-poetry/tomlkit@0.5.11...0.6.0)

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

Author: dependabot-preview[bot]

poetry.lock

@@ -10,7 +10,7 @@ homepage = "https://github.com/staticdev/toml-validator"
 
 [tool.poetry.dependencies]
 python = "^3.7"
-tomlkit = "^0.5.9"
+tomlkit = ">=0.5.9,<0.7.0"
 click = "^7.0"
 importlib_metadata = {version = "^1.6.0", python = "<3.8"}