Emit level field in structured (json) logging

[jcogilvie]

Describe the solution you'd like
Structured (i.e. json) logging should emit a level field (or equivalent) for use in indexing/parsing. Right now, the logs seem to emit the v field but no level, leaving it hard to distinguish what's an info vs. an error log in json.

Slack discussion indicates that potentially using something like vmware-tanzu/pinniped plog could help.

Anything else you would like to add:
I am using datadog as a log storage/search platform.

Environment:

• Secrets Store CSI Driver version: (use the image tag): v1.2.4
• Kubernetes version: (use kubectl version): 1.22

[nilekhc]

Ref: https://kubernetes.slack.com/archives/C013PUP2WRK/p1664505589573909

[enj]

I have exported vmware-tanzu/pinniped.plog into a standalone package at monis.app/mlog so that it can be easily used here. See #1134