Task: Rename a key in n8n

n8n workflow:
{"nodes":[{"name":"On clicking 'execute'","type":"n8n-nodes-base.manualTrigger","position":[250,320],"parameters":{},"typeVersion":1},{"name":"Set","type":"n8n-nodes-base.set","position":[450,320],"parameters":{"values":{"string":[{"name":"key","value":"somevalue"}]},"options":{}},"typeVersion":1},{"name":"Rename Keys","type":"n8n-nodes-base.renameKeys","position":[650,320],"parameters":{"keys":{"key":[{"newKey":"newkey","currentKey":"key"}]}},"typeVersion":1}],"connections":{"Set":{"main":[[{"node":"Rename Keys","type":"main","index":0}]]},"On clicking 'execute'":{"main":[[{"node":"Set","type":"main","index":0}]]}}}