Merge pull request #517 from effigies/mnt/cloudpickle2

MNT: Require cloudpickle >= 2.0

Author: djarecka

setup.cfg

@@ -25,7 +25,7 @@ classifiers =
 python_requires = >= 3.7
 install_requires =
     attrs >= 19.1.0
-    cloudpickle >= 1.2.2
+    cloudpickle >= 2.0.0
     filelock >= 3.0.0
     etelemetry >= 0.2.2