v3.0.0

This is a semver major release that drops support for Node 4 and Node 9. There are other breaking changes, but those should have zero to little impact for most users of this module.

Breaking Changes

• Node 4 and 9 are no longer supported.
• Distributed tracing in gRPC now uses a well-known metadata key that should enable distributed context propagation across services in other languages. The metadata key we used to use previously ended up being different from what the gRPC community has settled on. If you have mixture of services using v2 and v3 of this module, then distributed tracing may not work. We recommend moving all Node.js services up to v3 together.
• A few TypeScript types have been renamed. In particular, the object returned by start() and also passed to plugins is now called Tracer, instead of TraceAgent. This should have zero impact to JavaScript users, and a small impact to TypeScript users – only if the type TraceAgent was being explicitly being referred to in your code.

Commits

dde86d3 feat: rename TraceAgent/TraceApi to Tracer (#815)
4ac6ded fix: improve logs from the trace writer (#800)
63b13ca feat: use well-known format for propagating trace context thru grpc (#814)
f96c827 feat: implement (de)serialization of binary trace context (#812)
d146c5d chore(deps): update dependency gts to ^0.8.0 (#805)
1711db8 chore(deps): update dependency axios to ^0.18.0 (#804)
0a96e6c chore(deps): update dependency typescript to ~2.9.0 (#806)
93b7235 fix(deps): update dependency google-auto-auth to ^0.10.0 (#808)
fd138fc fix(deps): update dependency got to v8 (#811)
1fbbbf9 fix(deps): update dependency builtin-modules to v3 (#810)
94b8e3b fix(deps): update dependency gcp-metadata to ^0.7.0 (#807)
72cd353 refactor: convert plugin-grpc.ts to typescript (#799)
bff657a chore(deps): start using renovate (#801)
fa8f4a4 fix(package): update @google-cloud/common to version 0.20.3 (#796)
e4cfb1b chore: drop support for node 4 and 9 (#780)