Auto-merge dependabot PRs when all checks pass

[janisz]

Description

Currently @dependabot PRs are handled by @stackrox/ui-dep-updaters and @stackrox/backend-dep-updaters this is fine but many times updates are small and could be automatically merged.
This PR adds automation that will approve and post @dependabot squash and merge comment. PR will be merged if all checks pass (not only required ones).

Example: mdn/content#25142 (review)

Checklist

• Investigated and inspected CI test results
• Unit test and regression tests added
• Evaluated and added CHANGELOG entry if required
• Determined and documented upgrade steps
• Documented user facing changes (create PR based on openshift/openshift-docs and merge into rhacs-docs)

If any of these don't apply, please comment below.

Testing Performed

Tested it on kube-linter

• Auto merge dependabot PRs kube-linter#508

[ghost]

Images are ready for the commit at c036b81.

To use with deploy scripts, first export MAIN_IMAGE_TAG=3.74.x-308-gc036b81a16.

[vjwilson]

Unless we can exclude front-end dependencies, then we can't turn auto-merge on.

[janisz]

@vjwilson How about making it opt-in. If dependebot is configured to add auto-merge label then merge it automatically?

[openshift-ci]

@janisz: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/gke-postgres-qa-e2e-tests	c036b81	link	false	/test gke-postgres-qa-e2e-tests

Full PR test history. Your PR dashboard.

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