Workaround for Poetry 1.1

See python-poetry/poetry#3153 (comment)

Author: Frankie Robertson

pyproject.toml

@@ -26,7 +26,7 @@ sphinx-issues = {version = "^1.2.0", optional = true}
 [tool.poetry.dev-dependencies]
 
 [build-system]
-requires = ["poetry-core>=1.0.0"]
+requires = ["setuptools", "poetry-core>=1.0.0"]
 build-backend = "poetry.core.masonry.api"
 
 [tool.poetry.extras]