Add CURRENT_TIMESTAMP, CURRENT_DATE function support (linkedin#41)

Co-authored-by: Kai Xu <[email protected]>

Update Slack invitation link (linkedin#43)

Add support for Hive current_user function (linkedin#40)

Use Hive ANTLR grammar to parse HiveQL (linkedin#32)

 Migrate to new Shipkit plugins (linkedin#36)

- enables concurrent releases
 	- avoid unnecessary version bump commits
 	- enables using higher version of Gradle
 	- more info: https://github.com/mockito/shipkit/blob/master/docs/design-specs/future-shipkit.md
 - removed read-only token from checked-in files (even though it is read read-only, it should not be exposed to unexpected users/bots)

Created new tag v1.0.18 [ci skip]

Created new tag v1.0.17 [ci skip]

Created new tag v1.0.16 [ci skip]

Created new tag v1.0.15 [ci skip]

Created new tag v1.0.14 [ci skip]