Replace usage of github.com/gogo/protobuf

[vinny-sabatini]

gogo/protobuf is no longer maintained, and we should move away from it.

Here is the deprecation notification - gogo/protobuf#691 (comment)

[vinny-sabatini]

Per the Prometheus remote write specifications, we need to continue using gogo/protobuf. When Prometheus removes that requirement, we can come back to this issue, but that might not happen until the "Prometheus Remote Write 2.0" release.