Remove Flux.Data module

[mcabbott]

The contents of this was removed completely in Flux 0.13, except for MLUtils.DataLoader. The deprecation should let you still load this as if the module existed:

julia> Flux.Data
Flux

julia> Flux.Data.DataLoader(rand(Int8, 3,2)) |> collect
2-element Vector{Matrix{Int8}}:
 [11; 124; 119;;]
 [-4; -51; 111;;]

[mcabbott]

FastAI tests fail on UnicodePlots issue

Transformers.jl tests not run because of chengchingwen/Transformers.jl#96

Metalhead fails on some loading issue:

/home/runner/work/Flux.jl/Flux.jl/downstream/test/convnets.jl:29
507
Test threw exception
508
Expression: acctest(ResNet(sz, pretrain = true))
509
ArgumentError: Tried to load (Chain(Conv((7, 7), 3 => 64, pad=3, stride=2, bias=false), BatchNorm(64, relu), MaxPool((3, 3), pad=1, stride=2)), Chain(Chain(Parallel(PartialFunctions.PartialFunction{typeof(Metalhead.addact), Tuple{typeof(relu)}, NamedTuple{(), Tuple{}}}(Metalhead.addact, (NNlib.relu,), NamedTuple()), Chain(Conv((3, 3), 64 => 64, pad=1, bias=false), BatchNorm(64), relu, Conv((3, 3), 64 => 64, pad=1, bias=false), BatchNorm(64)), identity),

AtomicGraphNets fails on some DiffEq problem, SteadyStateAdjointProblem(sol::SciMLBase.NonlinearSolution{ ...