:bug: `mdformat-pyproject` not running properly

[miloth]

I found the following issue while investigating the task-runners. Running mdformat . --check will print files in .venv and .tox, even though there are settings to exclude them:

[tool.mdformat]
end_of_line = "lf"
exclude = [".tox/**", ".venv/**", "**/*.m[!d]", "**/*.[!m]d"]

This is due to the mdformat-pyproject plugin.