add open clip to train_config (#260)

add the ability to use open_clip in the train configs (useful for the new SOTA h/14 model)

dalle2_pytorch/train_configs.py

@@ -4,11 +4,13 @@ from pydantic import BaseModel, validator, root_validator
 from typing import List, Optional, Union, Tuple, Dict, Any, TypeVar
 
 from x_clip import CLIP as XCLIP
+from open_clip import list_pretrained
 from coca_pytorch import CoCa
 
 from dalle2_pytorch.dalle2_pytorch import (
     CoCaAdapter,
     OpenAIClipAdapter,
+    OpenClipAdapter,
     Unet,
     Decoder,
     DiffusionPrior,
@@ -117,6 +119,10 @@ class AdapterConfig(BaseModel):
     def create(self):
         if self.make == "openai":
             return OpenAIClipAdapter(self.model)
+        elif self.make == "open_clip":
+            pretrained = dict(list_pretrained())
+            checkpoint = pretrained[self.model]
+            return OpenClipAdapter(name=self.model, pretrained=checkpoint)
         elif self.make == "x-clip":
             return XClipAdapter(XCLIP(**self.base_model_kwargs))
         elif self.make == "coca":