Fix Poetry file

Author: oleg-nenashev

pyproject.toml

@@ -47,7 +47,7 @@ watchdog = "^3.0.0"
 wheel = "^0.40.0"
 pytest = "^7.3.1"
 
-[tool.poetry.docs]
+[tool.poetry.group.docs.dependencies]
 mkdocs = "^1.3.0"
 markdown_include = "^0.8.1"