Version 2.4.0

This release come with a few new features and some changed behaviors. Hopefully bringing us a tiny step towards scheduling heaven.

luigi:

• Luigi can now send error emails in easy-to-digest batches. #1916 Thanks @daveFNbuck
• New behavior for task.clone() #1630 Thanks @ChrisBeaumont
• Various bigquery improvements from @spotify engineers: #1888 #1917
• Add target.temporary_path() as a new recommended ways to deal with temporary paths in luigi #1909 (docs)

luigi.scheduler:

• Reverted the behavior introduced in 2.3.0. #1926

There have been a lot of other features, cleanups and bugfixes! See all commits
here.