[stable/prometheus-operator] allow to configure operator log level

[itaysk]

What this PR does / why we need it:

allows to configure operator log level (https://github.com/coreos/prometheus-operator/pull/1277/files)

Which issue this PR fixes

Special notes for your reviewer:

@gianrubio

Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• DCO signed
• Chart Version bumped
• Variables are documented in the README.md

[vsliouniaev]

/lgtm

[vsliouniaev]

/retest all

[vsliouniaev]

@itaysk can you please bump the chart version again?

[itaysk]

done

[vsliouniaev]

/lgtm
/retest

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: itaysk, vsliouniaev

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• stable/prometheus-operator/OWNERS [vsliouniaev]

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[k8s-ci-robot]

@vsliouniaev: Cannot trigger testing until a trusted user reviews the PR and leaves an /ok-to-test message.

In response to this:

/lgtm
/retest

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