estuary can't be build because of undefined blockstore.ErrNotFound calls

[fbac]

estuary can't be built due to undefined blockstore.ErrNotFound functions called:

# github.com/application-research/estuary/util/migratebs
util/migratebs/blockstore.go:132:34: undefined: blockstore.ErrNotFound
util/migratebs/blockstore.go:147:34: undefined: blockstore.ErrNotFound
util/migratebs/blockstore.go:185:34: undefined: blockstore.ErrNotFound

To Reproduce
Steps to reproduce the behavior:

1. Clone the repository
2. Run "make clean all" to start the build

Expected behavior
estuary correctly built

Actual behavior
estuary build fails because of undefined functions being called

Additional context
blockstore changed its way to raise ErrNotFound since this PR, which breaks compatibility.
The logic should be changed to use ipld.ErrNotFound instead of blockstore.ErrNotFound.

[alvin-reyes]

This is now fixed on the dev branch. Feel free to re-open this issue if you have concerns, alternatively you can reach out to us on our slack channel.