Walden snapshot available

[Casey Meyer]

Hi all,

As promised the first "Walden" snapshot is now available at s3://openalex/data! You can still get the last legacy snapshot at s3://openalex/legacy-data. 

The release notes are:

- switch to walden dataset
- works, authors, institutions, etc are from walden which is the default in the API
- includes "xpack" records in works, so full works count is 463M

As usual, please let us know if you find any bugs or issues.

Thanks,
Casey