Need to update the tutorial "Deep Learning with Flux - A 60 Minute Blitz"

[Ossifragus]

The following tutorial use using Metalhead: trainimgs, but the function trainimgs no longer exist in Metalhead.jl.

https://fluxml.ai/tutorials/2020/09/15/deep-learning-flux.html

[mcabbott]

After https://github.com/FluxML/fluxml.github.io/pull/156 this is deleted; moving the issue to the model zoo.