bump dependencies

- logrus 1.9.1 -> 1.9.4
- replace deprecated github.com/golang/protobuf with google.golang.org/protobuf
  (timestamppb.New / durationpb.New); JSON output is byte-identical because
  the legacy ptypes types are aliases of the new ones
- genproto pinned to v0.0.0-20250115164207-1a7da9e5054f (latest pseudo-version
  whose go directive is 1.22; newer ones require go 1.25.0)
- google.golang.org/protobuf pinned to v1.36.7 for the same reason (1.36.8+
  requires go 1.23)
- bump go directive 1.12 -> 1.22
- add Makefile with 'test' target

No exported API change; safe for existing consumers.

bump dependencies

Merge pull request #9 from crystal-construct/support-stackdriver

Added stackdriver severity compatibility, fixed panic logging