v2.0.0-alpha.1

chore: temporarily switch back to the old npm disttag (#12649)

The publishing of version 2.0.0-alpha.1 is failing because the build is
looking for the npm dist tag 'next' that doesn't yet exist.

This is temporarily switching the tag to use 'preview-v2'. Once the new
version is published, this change will be reverted.


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