Add support for tracking metrics with `Cloud Run` resource type

[hrvadl]

Hi!

Here we fallback to the generic task resource type:

It would be nice to somehow map resource attributes to the Cloud Run resource type. From what I know we need to have these labels to track it correctly:

• project_id
• revision_name
• service_name
• location
• configuration_name

OpenTelemetry collector with GCP resource detector collects the following attributes:

• cloud.platform (with the value of gcp_cloud_run) by which we can determine that this is the Cloud Run resource type
• faas.version -> revision_name?
• cloud.account.id -> project_id?
• cloud.region -> location?
• faas.name -> service_name?

[dashpole]

The main issue here is that we need the cloud run instance ID (faas.id) in order to differentiate between metrics from two different instances. Otherwise, you will get a variety of errors from the conflicting metrics.