v0.12.0

Minor feature release.

The Highlight:

• switch to synchronous gRPC requests

Changelog for v0.11.0..v0.12.0
* [df5b210] [maven-release-plugin] prepare for next development iteration
* [3979795] test: generate test certs only once
* [6402057] rpm: enforce older compression to support multiple distros
* [80d5917] drv: convert driver to use sync-rpc
* [08c3c29] [maven-release-plugin] prepare release v0.12.0