Motivation/summary

Leverage updatecli/updatecli#1914 and support commit signature verifications

Checklist

• Update CHANGELOG.asciidoc
• Documentation has been updated

For functional changes, consider:

• Is it observable through the addition of either logging or metrics?
• Is its use being published in telemetry to enable product improvement?
• Have system tests been added to avoid regression?

How to test these changes

I tested it in a playground:

• https://github.com/v1v/updatecli-demo/pull/43/commits

And also in my fork, for such I used this set of changes and tweaked a bit my main branch,

Then https://github.com/v1v/apm-server/pull/43/commits was created

Related issues

Then if it works as expected in the CI, changes will be applied to the remaining updatecli manifests