mypy says Library stubs not installed for "yaml"

[nesnoj]

With the pre-commit introduced in #64 this message persists:

digipipe/scripts/config.py:8: error: Library stubs not installed for "yaml"  [import]
digipipe/scripts/config.py:8: note: Hint: "python3 -m pip install types-PyYAML"
digipipe/scripts/config.py:8: note: (or run "mypy --install-types" to install all missing stub packages)
digipipe/scripts/config.py:8: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports

Both suggested solutions (pip install types-PyYAML and mypy --install-types) fixed the error. Do you wanna add it to the package list? Or shall we suppress it like @henhuy did as described in #64 (comment)?