Update README.md

Author: radoering

README.md

@@ -17,7 +17,7 @@ based project format.
 
 ```toml
 [build-system]
-requires = ["poetry-core>=1.0.0"]
+requires = ["poetry-core>=2.0.0,<3.0.0"]
 build-backend = "poetry.core.masonry.api"
 
 [project]