Bump versions to v1.2.0-incubating on release/v1.2

[xuang7]

Task Summary

Bump the project version to 1.2.0-incubating on the release/v1.2 branch,
in preparation for the v1.2.0-incubating release.

Changes (on release/v1.2):

• build.sbt: ThisBuild / version 1.1.0-incubating -> 1.2.0-incubating
• bin/k8s/values.yaml: imageTag 1.1.0-incubating -> 1.2.0-incubating

The docker-compose bundle pins the image tag via ${IMAGE_TAG} at RC time, so no change is needed there.

Task Type

• Refactor / Cleanup
• DevOps / Deployment / CI
• Testing / QA
• Documentation
• Performance
• Other

[Yicong-Huang]

@xuang7 is this done?