1.x branch: bump to 1.21.0 to make a release.

Version bump for a release.

Bump to 1.20.2 for a release.

Version bump for another release

Version bump for a release

version bump to get a 1.x release for the negative small Duration jso…

…n parsing fix

Version bump for a release.

Version bump in preparation for a release.

Version bump for a release.

Version bump to make a release.