[chore] Use `pull_request_target` event to trigger "add codeowners" workflow (#16228)
[chore] Use `pull_request_target` event to trigger "add codeowners" workflow (#16228)

Use `pull_request_target` event to trigger "add codeowners to PR" workflow

Co-authored-by: Evan Bradley <7ec9efafb38d7f6df6c8b37431ca5cc59dc38bad@users.noreply.github.com>
open-telemetry/opentelemetry-collector-contrib,open-telemetry/opentelemetry-collector-contrib