Require version of ChainRulesCore with MutableTangent etc

Author: oxinabox

Project.toml

@@ -18,7 +18,7 @@ StructArrays = "09ab397b-f2b6-538f-b94a-2f83cf4a842a"
 [compat]
 AbstractDifferentiation = "0.5"
 ChainRules = "1.44.6"
-ChainRulesCore = "1.15.3"
+ChainRulesCore = "1.20"
 Combinatorics = "1"
 Cthulhu = "2"
 OffsetArrays = "1"