v0.21.0-beta1

Added

• Moved to Go modules.
• Add COMMIT_STATS function
• sql: implement EXPLODE and generators (#720)

Changed

• Upgrade vitess to v1.8.0 (#738)
• Upgrade bblfsh to v4.1.0.
• Upgrade gocloc to latest master 764f3f6ae21e.

Fixed

• Fix parsing of quoted identifiers in SHOW CREATE TABLE queries (#737)
• sql/analyzer: back-propagate expression names after adding convert (#739)
• sql/expression: allow null literals in case branches (#741)
• sql/plan: make LEFT and RIGHT join work as expected (#743)