Task: Demonstrates the use of the $item(index) method

n8n workflow JSON:
{"nodes":[{"name":"On clicking 'execute'","type":"n8n-nodes-base.manualTrigger","position":[250,300],"parameters":{},"typeVersion":1},{"name":"Set","type":"n8n-nodes-base.set","position":[450,300],"parameters":{"values":{"string":[{"name":"apiKey","value":"n8n-secret-keey"}]},"options":{},"keepOnlySet":true},"typeVersion":1},{"name":"Customer Datastore","type":"n8n-nodes-base.n8nTrainingCustomerDatastore","position":[650,300],"parameters":{"operation":"getAllPeople","returnAll":true},"typeVersion":1},{"name":"HTTP Request","type":"n8n-nodes-base.httpRequest","position":[850,300],"parameters":{"url":"https://webhook.site/f99d65ab-8959-4466-a427-cdd0ad482220","options":{},"requestMethod":"POST","bodyParametersUi":{"parameter":[{"name":"name","value":"={{$json[\"name\"]}}"}]},"headerParametersUi":{"parameter":[{"name":"api-key","value":"={{ $item(0).$node[\"Set\"].json[\"apiKey\"] }}"}]}},"typeVersion":1}],"connections":{"Set":{"main":[[{"node":"Customer Datastore","type":"main","index":0}]]},"Customer Datastore":{"main":[[{"node":"HTTP Request","type":"main","index":0}]]},"On clicking 'execute'":{"main":[[{"node":"Set","type":"main","index":0}]]}}}