problem with downloading datase: SyntaxError: (repo_commit_hash=)

Thanks for the amazing work! But i have a problem when downloading the dataset:

```
import objaverse.xl as oxl

annotations = oxl.get_annotations(
download_dir="~/.objaverse" # default download directory
)
annotations

print(annotations)
```

when im runing this code, i encountered this error:
```
Traceback (most recent call last):
File "/home/ubuntu/Desktop/xxx/objaverse/test.py", line 2, in
import objaverse.xl as oxl
File "/home/ubuntu/anaconda3/envs/rl/lib/python3.7/site-packages/objaverse/xl/__init__.py", line 7, in
from objaverse.xl.github import GitHubDownloader
File "", line 1
(repo_commit_hash=)
^
SyntaxError: invalid syntax
```

im on a ubuntu20.4