Improper version of go in go.mod

[pellared]

Currently the otlp/go.mod has:

opentelemetry-proto-go/otlp/go.mod

Line 3 in 53bebda

go 1.17

Notice that the Go module depends on:

opentelemetry-proto-go/otlp/go.mod

Line 7 in 53bebda

google.golang.org/grpc v1.67.1

Which requires Go 1.21: https://github.com/grpc/grpc-go/blob/v1.67.1/go.mod#L3

Therefore, in otlp/go.mod we should have go 1.21.

It look like that there is no GitHub workflows that tests if the generated code actually builds.

I think that renovate (instead of dependabot) would be able to bump the Go version.

Bug found when reviewing #194 (comment)