Error parsing pyproject.tml

Describe the bug

Hi ! I'm following the documentation** to provide a custom setup for bandit to exclude some tests (B101) in our testing framework but I get the following error:

[config]        ERROR   expected '<document start>', but found '<scalar>'
  in "pyproject.toml", line 2, column 1
[main]  ERROR   pyproject.toml : Error parsing file

Where the ppyproject.toml is the following

[tool.black]
line-length = 120
skip-string-normalization = true
skip-magic-trailing-comma = true


[tool.bandit.assert_used]
exclude = ["*_test.py", "test_*.py"]

**https://bandit.readthedocs.io/en/latest/config.html

Reproduction steps

1. bandit --recursive -c pyproject.toml test

Expected behavior

Not crash

Bandit version

1.7.0 (Default)

Python version

3.8

Additional context

No response

Reproduce the failure with the reported pyproject.toml and bandit --recursive -c pyproject.toml test command. Trace the configuration parsing entry point and verify that the shown Bandit settings are accepted without the parsing error and that the exclude patterns take effect.