Why is black a dependency?

[NeilGirdhar]

It doesn't seem to be imported anywhere.

[krassowski]

It is used here:

python-lsp-server/pylsp/_utils.py

Lines 258 to 259 in 8c96441

	class BlackFormatter(Formatter):
	command = ["black"]

See #631

[alecbcs]

@krassowski could the dependency on black be optional? It seems like ruff can also be used in place of black here, but since black is set as a required dependency it is installed regardless of a project's configuration.