Task: Create a channel, add a member, and post a message to the channel on Mattermost

n8n workflow JSON:
{"id":"178","name":"Create a channel, add a member, and post a message to the channel","nodes":[{"name":"On clicking 'execute'","type":"n8n-nodes-base.manualTrigger","position":[270,340],"parameters":{},"typeVersion":1},{"name":"Mattermost","type":"n8n-nodes-base.mattermost","position":[470,340],"parameters":{"teamId":"4zhpirmh97fn7jgp7qhyue5a6e","channel":"docs","resource":"channel","displayName":"Docs"},"credentials":{"mattermostApi":"Mattermost Credentials"},"typeVersion":1},{"name":"Mattermost1","type":"n8n-nodes-base.mattermost","position":[670,340],"parameters":{"userId":"5oiy71hukjgd9eprj1o4a3poio","resource":"channel","channelId":"={{$node[\"Mattermost\"].json[\"id\"]}}","operation":"addUser"},"credentials":{"mattermostApi":"Mattermost Credentials"},"typeVersion":1},{"name":"Mattermost2","type":"n8n-nodes-base.mattermost","position":[870,340],"parameters":{"message":"Hey! Welcome to the channel!","channelId":"={{$node[\"Mattermost\"].json[\"id\"]}}","attachments":[],"otherOptions":{}},"credentials":{"mattermostApi":"Mattermost Credentials"},"typeVersion":1}],"active":false,"settings":{},"connections":{"Mattermost":{"main":[[{"node":"Mattermost1","type":"main","index":0}]]},"Mattermost1":{"main":[[{"node":"Mattermost2","type":"main","index":0}]]},"On clicking 'execute'":{"main":[[{"node":"Mattermost","type":"main","index":0}]]}}}