Support Cloud Run Monitored Resource

[meltsufin]

Is your feature request related to a problem? Please describe.

Spring Cloud GCP Logging does not work with Cloud Run. The logs end up in the "Global" channel rather than the one for Cloud Run.

Describe the solution you'd like

The Cloud Run resource type cloud_run_revision should be automatically assigned to the log entries, similarly to how it's done for App Engine. See: MonitoredResourceUtil.

Describe alternatives you've considered

Using JSON-based logging on Cloud Run. It works better but has other issues like not supporting TRACE and WARN levels.

Additional context

Repro: https://github.com/meltsufin/cloud-run-helloworld

[saturnism]

Ideally, there is a single public API call to retrieve/produce a MonitoredResource. This is a common library as oppose to only for logs.