release: prepare to release v0.21.0

release: prepare to release v0.21.0-rc2

release: prepare to release v0.21.0-rc1

This updates embedded version numbers, and also updates the
C++ jsonnet dependency to the published v0.21.0-rc1 (source release).

Bump version to 0.20.0 (#688)

adding jsonnet-deps to release (#667)

Co-authored-by: Jordan Cohen <jordan.cohen@digitalasset.com>

Adds jsonnet-lint to the releases (#664)

Bump version to v0.19.1

Update version to v0.19.0

Prepare for v0.18.0

Release 0.17.0