Remove Flux.Data module (#2126)

* remove Flux.Data module

* don't export Data by accident

Author: mcabbott

src/Flux.jl

@@ -61,10 +61,6 @@ include("loading.jl")
 include("outputsize.jl")
 export @autosize
 
-include("data/Data.jl")
-using .Data
-
-
 include("losses/Losses.jl")
 using .Losses # TODO: stop importing Losses in Flux's namespace in v0.12
 

src/data/Data.jl

@@ -81,6 +81,9 @@ Base.@deprecate_binding OADAM OAdam
 Base.@deprecate_binding ADAGrad AdaGrad
 Base.@deprecate_binding ADADelta AdaDelta
 
+# Remove sub-module Data, while making sure Flux.Data.DataLoader keeps working
+Base.@deprecate_binding Data Flux false "Sub-module Flux.Data has been removed. The only thing it contained may be accessed as Flux.DataLoader"
+
 @deprecate rng_from_array() default_rng_value()
 
 #=