--- pyproject.toml.orig	2020-01-09 18:52:35 UTC
+++ pyproject.toml
@@ -1,5 +1,5 @@
 [build-system]
-requires = ["flit_core >=2,<3"]
+requires = ["flit_core >=2,<4"]
 build-backend = "flit_core.buildapi"
 
 [tool.flit.metadata]