migrate azure blob for beit checkpoints (#16902)

## Motivation

We are going to use a new blob account to store the checkpoints.

## Modification

Modify the azure blob storage URLs for BEiT checkpoints.

src/transformers/models/beit/convert_beit_unilm_to_pytorch.py

@@ -359,7 +359,7 @@ def convert_beit_checkpoint(checkpoint_url, pytorch_dump_folder_path):
 
     parser.add_argument(
         "--checkpoint_url",
-        default="https://unilm.blob.core.windows.net/beit/beit_base_patch16_224_pt22k_ft22kto1k.pth",
+        default="https://conversationhub.blob.core.windows.net/beit-share-public/beit/beit_base_patch16_224_pt22k_ft22kto1k.pth",
         type=str,
         help="URL to the original PyTorch checkpoint (.pth file).",
     )