Fix ASSET dataset data URLs
> Hi @tianjianjiang, thanks for the fix.
> The links should also be updated in the `dataset_infos.json` file.
> The failing tests are due to the missing tag in the header of the `README.md` file:

Hi @albertvillanova, thank you for the info! My apologies for the messy PR.

Change the branch name "master" to "main" in the data URLs, since facebookresearch has changed that.