v3 "PRUE" release

This release contains a new series of models corresponding to the configs at configs/release/prue/:

• prue_efnet{3,5,7}_checkpoint.ckpt are 3-class U-Net models trained with channel shuffle, normalization augmentation, resize augmentation, a logcosh dice loss function, class weighting of background:0.05, field:0.2, field boundary:0.75 and efficientnet b{3,5,7} encoders on the full FTW dataset.
• prue_efnet{3,5,7}_standard_weight_checkpoint.ckpt are the same as above, but using the same class weights as the v1 models.
• prue_logcoshdice_only_checkpoint.ckpt is the same as the v1 model, but using a logcosh dice loss function.

We find these models outperform the previously released models in both performance and deployment metrics.