New models to add

[notprime]

Just a list of new models we should add to torchseg.
Feel free to comment if you'd like to see any model to be added or if you want to share personal experiences regarding specific archs!

:D

[notprime]

• UperNet
• SegNext

[ZappaRoberto]

Hi, I think you should consider to implement also UNET 3+ (https://arxiv.org/pdf/2004.08790).
In my experience perform bettern than standard Unet or Unet++ :) .

[JulienMaille]

You could probably start from this PR qubvel-org#474

[GMoncrieff]

FeatUp looks like a great new decoder (both the JBU and implicit upsamplers). There is an open issue in the smp repo, but nothing has happened since March.

[isaaccorley]

I've been using this recently so will definitely add it ASAP!