Task: Notify on new document in Google Drive folder

n8n workflow:
{"id":3,"name":"New scans","nodes":[{"name":"On clicking 'execute'","type":"n8n-nodes-base.manualTrigger","position":[250,300],"parameters":{},"typeVersion":1},{"name":"Google Drive","type":"n8n-nodes-base.googleDrive","position":[450,300],"parameters":{"limit":500,"options":{"fields":["*"]},"operation":"list","queryString":"='FOLDER_ID_HERE' in parents","authentication":"oAuth2","useQueryString":true},"credentials":{"googleDriveOAuth2Api":"Google Drive account"},"typeVersion":1},{"name":"IF","type":"n8n-nodes-base.if","position":[850,300],"parameters":{"conditions":{"number":[],"dateTime":[{"value1":"={{$json[\"createdTime\"]}}","value2":"={{$json[\"latestRead\"]}}"}]}},"typeVersion":1},{"name":"Cron","type":"n8n-nodes-base.cron","position":[260,560],"parameters":{"triggerTimes":{"item":[{"mode":"custom","cronExpression":"*/30 9-17 * * 1-5"}]}},"typeVersion":1},{"name":"Function1","type":"n8n-nodes-base.function","position":[1050,300],"parameters":{"functionCode":"const staticData = this.getWorkflowStaticData('global');\nstaticData.latestRead = (new Date()).toUTCString();\nreturn items;\n"},"typeVersion":1},{"name":"Function","type":"n8n-nodes-base.function","position":[650,300],"parameters":{"functionCode":"const staticData = this.getWorkflowStaticData('global');\n\nlatestRead = staticData.latestRead;\nfor (let item of items) {\n  item.json.latestRead = latestRead || '1970-01-01';\n}\nreturn items;\n"},"typeVersion":1},{"name":"Mattermost","type":"n8n-nodes-base.mattermost","position":[1250,300],"parameters":{"channelId":"57grbom5w7ga7nxfaiuz5m9ezo","attachments":[{"title":"={{$node[\"Google Drive\"].json[\"name\"]}}","title_link":"={{$node[\"Google Drive\"].json[\"webViewLink\"]}}"}],"otherOptions":{}},"typeVersion":1}],"active":true,"settings":{},"connections":{"IF":{"main":[[{"node":"Function1","type":"main","index":0}]]},"Cron":{"main":[[{"node":"Google Drive","type":"main","index":0}]]},"Function":{"main":[[{"node":"IF","type":"main","index":0}]]},"Function1":{"main":[[{"node":"Mattermost","type":"main","index":0}]]},"Google Drive":{"main":[[{"node":"Function","type":"main","index":0}]]},"On clicking 'execute'":{"main":[[{"node":"Google Drive","type":"main","index":0}]]}}}