Task: Send a message via AWS SNS

n8n workflow JSON:
{"nodes":[{"name":"On clicking 'execute'","type":"n8n-nodes-base.manualTrigger","position":[250,300],"parameters":{},"typeVersion":1},{"name":"AWS SNS","type":"n8n-nodes-base.awsSns","position":[450,300],"parameters":{"topic":"n8n-rocks","message":"This is a test message","subject":"This is a test subject"},"credentials":{"aws":"aws"},"typeVersion":1}],"connections":{"On clicking 'execute'":{"main":[[{"node":"AWS SNS","type":"main","index":0}]]}}}