move build to flit

Author: Carreau

pyproject.toml

@@ -1,6 +1,6 @@
 [build-system]
-build-backend = "setuptools.build_meta"
-requires = ["setuptools"]
+build-backend = "flit_core.buildapi"
+requires = ["flit_core>=3.2"]
 
 [project]
 name = "matplotlib-inline"