Implement HASH_CODE operator for JSON type
Document DATE memory representation change
Fix window functions with no input channels
Add missing calls to declarePosition

Also, validate that blocks have the same number of positions as the
declared positions in the page to catch these issues in the future
Fix PageBuilder.isEmpty()

It was relying on BlockBuilderStatus.isEmpty, which tracks size.
Entry size can be 0 under certain conditions, which causes PageBuilder
to say it's empty when it's not.
Show empty rows for Values in explain
Fail task when local planning fails
Add release note for JOIN bug
Add release notes for 0.89
Update to airlift 0.99
Update to tpch 0.4
[maven-release-plugin] prepare release 0.89
[maven-release-plugin] prepare for next development iteration
CAST to UNKNOWN should not be allowed
Added map_agg aggregation function
Add getColumnTypes API to RecordSink
Add PageSink to SPI
Add release notes for ConnectorPageSink