params() is no longer supported in Flux

[halyusuf25]

When trying to run any example experiment with neural net i got the following error:
ERROR: UndefVarError: params not defined

tracing back the error and found that it always come from the Flux function params, for example when running the JuliaRL_BCQD_CartPole.jl experiment the error comes from neural_network_approximator object and more specifically from this function
function Base.copyto!(dest::ActorCritic, src::ActorCritic) Flux.loadparams!(dest.actor, params(src.actor)) Flux.loadparams!(dest.critic, params(src.critic)) end

After some google search i found that params() function was supported in Flux <= version 0.12 but it was removed in version 0.13
https://fluxml.ai/Flux.jl/stable/training/reference/#Flux.params
i tried "using Flux: params" but it gives me the same error...

im creating this issue because this change is impacting almost all experiments examples.

[HenriDeh]

I'm closing since this is a duplicate of #982