add missing flags to L_vlb models in README

Author: unixpickle

README.md

@@ -133,14 +133,14 @@ Unconditional ImageNet-64 with the `L_vlb` objective and cosine noise schedule [
 
 ```bash
 MODEL_FLAGS="--image_size 64 --num_channels 128 --num_res_blocks 3 --learn_sigma True"
-DIFFUSION_FLAGS="--diffusion_steps 4000 --noise_schedule cosine"
+DIFFUSION_FLAGS="--diffusion_steps 4000 --noise_schedule cosine --use_kl True"
 TRAIN_FLAGS="--lr 1e-4 --batch_size 128 --schedule_sampler loss-second-moment"
 ```
 
 Unconditional CIFAR-10 with the `L_vlb` objective and cosine noise schedule [[checkpoint](https://openaipublic.blob.core.windows.net/diffusion/march-2021/cifar10_uncond_vlb_50M_500K.pt)]:
 
 ```bash
 MODEL_FLAGS="--image_size 32 --num_channels 128 --num_res_blocks 3 --learn_sigma True --dropout 0.3"
-DIFFUSION_FLAGS="--diffusion_steps 4000 --noise_schedule cosine"
+DIFFUSION_FLAGS="--diffusion_steps 4000 --noise_schedule cosine --use_kl True"
 TRAIN_FLAGS="--lr 1e-4 --batch_size 128 --schedule_sampler loss-second-moment"
 ```