Run yarn-deduplicate on yarn.lock to dedupe packages. This is being done
to reduce the number of redundant packages fetched by yarn when existing
versions in the lockfile satisfy the version dependency we need.
See https://github.com/scinos/yarn-deduplicate for details on the tool
used to perform this deduplication.
Updates #cleanup
Signed-off-by: Mario Minardi <mario@tailscale.com>