Bulk upgrade agents
[Required authorization] Route required privileges: fleet-agents-all.
POST
/api/fleet/agents/bulk_upgrade
curl \
--request POST 'https://<KIBANA_URL>/api/fleet/agents/bulk_upgrade' \
--header "Authorization: $API_KEY" \
--header "Content-Type: application/json" \
--header "kbn-xsrf: true" \
--data '{"agents":["string"],"batchSize":42.0,"force":true,"includeInactive":false,"rollout_duration_seconds":42.0,"skipRateLimitCheck":true,"source_uri":"string","start_time":"string","version":"string"}'