[exporter/newrelic] instrumentation.provider attribute is missing

[F21]

Describe the bug
According to the opentelemetry spec for new relic, there should be an instrumentation.provider attribute:https://github.com/newrelic/newrelic-exporter-specs/blob/master/opentelemetry/OpenTelemetry-Spans.md

This appears to be missing in the exporter and spans sent to new relic are missing this attribute.

Steps to reproduce

1. Instrument an app (I used the Go SDK)
2. Point the app to use an opentelemetry collector with the new relic exporter.
3. Filter entities in the explorer with instrumentation.provider = opentelemetry and see that the entities do not show up.

What did you expect to see?
Spans sent to new relic should have the instrumentation.provider attribute set.

What did you see instead?
The instrumentation.provider attribute was not set.

What version did you use?
v0.21.0

What config did you use?

receivers:
  otlp:
    protocols:
      grpc:
processors:
  batch:
exporters:
  newrelic:
    apikey: NEW_RELIC_KEY_GOES_HERE
    timeout: 30s
service:
  pipelines:
    traces:
      receivers: [otlp]
      processors: [batch]
      exporters: [newrelic]
    metrics:
      receivers: [otlp]
      processors: [batch]
      exporters: [newrelic]

Environment
OS: Minikube in docker mode

[gunturaf]

I came across this issue too, this causes my Traces to only visible on the "Distributed Tracing" page in the One UI APM page, while not being visible as Transactions in the APM.

Firstly I came across this code in the newrelic/opentelemetry-exporter-go repo. https://github.com/newrelic/opentelemetry-exporter-go/blob/e563425c51c9e256b329c37e72192baac0396aca/newrelic/internal/transform/span.go#L63

My traces will correctly shown in the Transactions page when I manually add the instrumentation.provider = opentelemetry attribute to my Traces. The immediate workaround I did was like this:

serviceAttr := resource.NewWithAttributes(
	semconv.ServiceNameKey.String("something-something"),
	semconv.ServiceNamespaceKey.String("group-of-something"),
	attribute.String("instrumentation.provider", "opentelemetry"), // add this one
)
pusher := otelController.New(
	// other opts...
	otelController.WithResource(serviceAttr),
)

I'll volunteer for PR if this issue is confirmed.

cc-ing NR code owners @alanwest @a-feld @jack-berg @nrcventura

[F21]

Fixed in #2900