Enable torch.load weights_only=True

Change torch.load to use the safer option of only loading weights.
The torch.load function is hard coded to use the default value
within the open_clip package. The code will set
TORCH_FORCE_WEIGHTS_ONLY_LOAD environment variable to 'true' if
not already set to override the default.

Fixes #32

src/bioclip/predict.py

@@ -1,3 +1,4 @@
+import os
 import json
 import torch
 from torchvision import transforms
@@ -19,6 +20,13 @@
 PRED_CLASSICATION_KEY = "classification"
 PRED_SCORE_KEY = "score"
 
+
+# Use secure model loading unless explicitly disabled.
+# See https://github.com/pytorch/pytorch/blob/main/SECURITY.md#untrusted-models for more.
+if not "TORCH_FORCE_WEIGHTS_ONLY_LOAD" in os.environ:
+    os.environ["TORCH_FORCE_WEIGHTS_ONLY_LOAD"] = "true"
+
+
 OPENA_AI_IMAGENET_TEMPLATE = [
     lambda c: f"a bad photo of a {c}.",
     lambda c: f"a photo of many {c}.",