fix: correct build backend name to use underscores for pip compatibility

Author: micaelaw

pyproject.toml

@@ -71,4 +71,4 @@ relative_files = true
 
 [build-system]
 requires = ["poetry-core>=1.0.0", "poetry-dynamic-versioning>=1.0.0,<2.0.0"]
-build-backend = "poetry-dynamic-versioning.backend"
+build-backend = "poetry_dynamic_versioning.backend"