Thew latest version of yarn includes a new integrity field for all
package entries.
Regenerate our yarn.lock files so that they are fully updated to the
latest file format.
Update grpc to v1.12.3 in order to fix issues build issues due to the fact
that 1.12.1 doesn't contain node-pre-gyp as a bundled dependency.
See https://github.com/grpc/grpc-node/issues/365
The impetus is to improve error reporting for GRPC connection errors,
which was introduced in 1.8.4. Security and other fixes are included
as well.
https://github.com/grpc/grpc-node/releases