reinstate the TemporalBrains tutorial #603
Description
It has been removed in #602 since the dataset takes too long to download. It can be found in GraphNeuralNetworks/docs/old_tutorials/temporal_graph_classification.jl. We can try to reintegrate it and see how much additional CI time it would take, than decide if we want it or not.
As an alternative, maybe a smaller version of the dataset can be added to MLDatasets.jl