Overriding Base.getproperty(vds::Vector{DataStore}, s::Symbol) conflicts A.ref usage in julia

[goulf-3m]

This code fails in newer versions of Julia:

fill(GraphNeuralNetworks.DataStore(), 3)

The implementation of fill will ultimately use A.ref, where A is a Vector{DataStore}.
However, A.ref is overridden by this package, and will be interpreted as accessing GNN data.

This overload should check this condition (s===:ref) and use getfield(vds, :ref).

[CarloLucibello]

thanks for investigating this. fix pushed in #505