fix params not defined issues

Author: hmyuuu

src/Algorithm/DDPG.jl

@@ -1,9 +1,11 @@
 ## TODO: Need reconstruct !!!
 using Flux: glorot_normal, glorot_uniform
 using StableRNGs
-using Flux.Losses
 using IntervalSets
 
+Base.copyto!(dest::ReinforcementLearning.NeuralNetworkApproximator, src::ReinforcementLearning.NeuralNetworkApproximator) =
+           Flux.loadparams!(dest.model, Flux.params(src))
+
 function Base.rsplit( v, l::Int)
     u = reshape(v,l,length(v)÷l)
     [u[:,i] for i=1:size(u,2)]