fix typo in changelog

Author: penelopeysm

HISTORY.md

@@ -1,6 +1,6 @@
 # Release 0.38.3
 
-`getparams(::Model, ::AbstractVarInfo)` now returns an empty `Float64` if the VarInfo contains no parameters.
+`getparams(::Model, ::AbstractVarInfo)` now returns an empty `Float64[]` if the VarInfo contains no parameters.
 
 # Release 0.38.2