Added anesthetic as an optional dependency

pyproject.toml

@@ -43,6 +43,7 @@ classifiers = [
 [project.optional-dependencies]
 docs = ["sphinx", "sphinx_rtd_theme", "numpydoc"]
 test = ["pytest", "pytest-cov", "flake8", "pydocstyle", "packaging", "pre-commit"]
+plot = ["anesthetic",]
 
 [tool.setuptools.dynamic]
 version = {attr = "lsbi._version.__version__"}