RepoIndexResult: Fix type of hash. (#729)
RepoIndexResult: Fix type of hash. (#729)

This should be a BlobProperty, not BlobKeyProperty.

Since this is in the Python model where writing isn't done, we don't
have to migrate
any existing entities.
google/osv.dev,google/osv.dev,google/osv.dev,google/osv.dev,google/osv.dev