fix S3Target import

Upgrade luigi to 2.8.0

Merge pull request #38 from opendoor-labs/check-existing-buffer

Use try-except to see if buffer was opened

Only close the buffer if the buffer exists

Merge pull request #36 from opendoor-labs/add-datadog-flush

Add ThreadStats, remove close buffer from Exception, add types

Merge branch 'master' of github.com:opendoor-labs/fireflower into add-datadog-flush

Register datadog, so datadog metrics can be flushed

Add a utility function to get pending tasks (#35)

Merge pull request #32 from opendoor-labs/update-luigi

update luigi from 2.3.2 to 2.6.0

Merge pull request #31 from opendoor-labs/pr-0-logger-new

logger.new to avoid leaking logger.bind; also log task_uuid

FireflowerS3Target: Fix format=Nop with local_s3_path (e.g. monsoon passthru compression) (#30)