Upgrade otel/build-protobuf image 0.2.1->0.11.0

[MrAlias]

Fix #45

• Upgrades github.com/grpc-ecosystem/grpc-gateway v1.16.0 -> v2.7.0 (last version that supports Go 1.14 and resolves vulnerability)
• Switch from github.com/golang/protobuf to google.golang.org/protobuf entirely.

[MrAlias]

Looking at options to address Go 1.17 min requirement. Might be worth following suit for the repo.

[Aneurysm9]

Can we use github.com/grpc-ecosystem/grpc-gateway@v2.7.0? That seems to be the most recent version that doesn't explicitly require 1.17.

[MrAlias]

Can we use github.com/grpc-ecosystem/grpc-gateway@v2.7.0? That seems to be the most recent version that doesn't explicitly require 1.17.

It doesn't look like there is a release that supports that version. v0.8.0 brings in these dependencies:

go: creating new go.mod: module go.opentelemetry.io/proto/otlp
go: to add module requirements and sums:
	go mod tidy
go: module github.com/golang/protobuf is deprecated: Use the "google.golang.org/protobuf" module instead.
go: added github.com/golang/protobuf v1.5.2
go: added github.com/grpc-ecosystem/grpc-gateway v1.16.0
go: added google.golang.org/grpc v1.45.0
go: added google.golang.org/protobuf v1.28.0

and v0.9.0:

go: creating new go.mod: module go.opentelemetry.io/proto/otlp
go: to add module requirements and sums:
	go mod tidy
go: added github.com/grpc-ecosystem/grpc-gateway/v2 v2.10.0
go: added google.golang.org/grpc v1.45.0
go: added google.golang.org/protobuf v1.28.0

[MrAlias]

Given there is a security issue this is resolving, it seems to motivate moving forward to Go 1.17 early.

[MrAlias]

@Aneurysm9 PTAL. I think I've figured out a way to upgrade reliably to where we want github.com/grpc-ecosystem/grpc-gateway and keep backwards compatible support.