Task: Sync Zendesk tickets with subsequent comments to GitHub issues

n8n workflow JSON:
{"meta":{"instanceId":"237600ca44303ce91fa31ee72babcdc8493f55ee2c0e8aa2b78b3b4ce6f70bd9"},"nodes":[{"id":"f0913aa6-4e78-4808-b828-7e9953e71764","name":"Get ticket","type":"n8n-nodes-base.zendesk","position":[380,480],"parameters":{"id":"={{$node[\"On new Zendesk ticket\"].json[\"body\"][\"id\"]}}","operation":"get"},"credentials":{"zendeskApi":{"id":"24","name":"[UPDATE ME]"}},"typeVersion":1},{"id":"f8774217-bc05-4b02-8632-154654f79d5f","name":"IF","type":"n8n-nodes-base.if","position":[780,480],"parameters":{"conditions":{"string":[{"value1":"={{$node[\"Determine\"].json[\"GitHub Issue Number\"]}}","operation":"isNotEmpty"}]}},"typeVersion":1},{"id":"6ae7e40b-b75c-41e2-9ba7-bb299f12911a","name":"Update ticket","type":"n8n-nodes-base.zendesk","notes":"Update the Zendesk ticket by adding the Jira issue key to the \"Jira Issue Key\" field.","position":[1180,580],"parameters":{"id":"={{$node[\"On new Zendesk ticket\"].json[\"body\"][\"id\"]}}","operation":"update","updateFields":{"customFieldsUi":{"customFieldsValues":[{"id":6721726848029,"value":"={{$node[\"Create issue\"].json[\"number\"]}}"}]}}},"credentials":{"zendeskApi":{"id":"24","name":"[UPDATE ME]"}},"notesInFlow":true,"typeVersion":1},{"id":"7959986c-cfbf-4ba2-a968-95b62d2aa819","name":"Determine","type":"n8n-nodes-base.function","notes":"if issue was created already in Jira","position":[580,480],"parameters":{"functionCode":"/* configure here =========================================================== */\n/*  Zendesk field ID which represents the \"GitHub Issue Number\" field.\n*/\nconst ISSUE_KEY_FIELD_ID = 6721726848029;\n\n/* ========================================================================== */\nnew_items = [];\n\nfor (item of $items(\"Get ticket\")) {\n    \n    // instantiate a new variable for status\n    var custom_fields = item.json[\"custom_fields\"];\n    var github_issue_number = \"\";\n    for (var i = 0; i < custom_fields.length; i++) {\n        if (custom_fields[i].id == ISSUE_KEY_FIELD_ID) {\n            github_issue_number = custom_fields[i].value;\n            break;\n        }\n    }\n\n    // push the new item to the new_items array\n    new_items.push({\n        \"GitHub Issue Number\": github_issue_number\n    });\n}\n\nreturn new_items;"},"notesInFlow":true,"typeVersion":1},{"id":"a1ca21d3-958f-498c-a896-05d4ecbc286d","name":"Create issue","type":"n8n-nodes-base.github","position":[980,580],"parameters":{"owner":"John-n8n","title":"={{$node[\"Get ticket\"].json[\"subject\"]}}","labels":[],"assignees":[],"repository":"DemoRepo"},"credentials":{"githubApi":{"id":"20","name":"[UPDATE ME]"}},"typeVersion":1},{"id":"1ad6f536-2cdb-4ecc-85b4-2e960fb84498","name":"Create comment on existing issue","type":"n8n-nodes-base.github","position":[980,380],"parameters":{"body":"={{$node[\"On new Zendesk ticket\"].json[\"body\"][\"comment\"]}}","owner":"John-n8n","operation":"createComment","repository":"DemoRepo","issueNumber":"={{$node[\"Determine\"].json[\"GitHub Issue Number\"]}}"},"credentials":{"githubApi":{"id":"20","name":"[UPDATE ME]"}},"typeVersion":1},{"id":"73e8c380-63de-4e5a-8e57-a17956174869","name":"On new Zendesk ticket","type":"n8n-nodes-base.webhook","position":[180,480],"webhookId":"b4253880-b5e2-4d61-bb2a-b0ea335bee14","parameters":{"path":"b4253880-b5e2-4d61-bb2a-b0ea335bee14","options":{},"httpMethod":"POST"},"typeVersion":1}],"connections":{"IF":{"main":[[{"node":"Create comment on existing issue","type":"main","index":0}],[{"node":"Create issue","type":"main","index":0}]]},"Determine":{"main":[[{"node":"IF","type":"main","index":0}]]},"Get ticket":{"main":[[{"node":"Determine","type":"main","index":0}]]},"Create issue":{"main":[[{"node":"Update ticket","type":"main","index":0}]]},"On new Zendesk ticket":{"main":[[{"node":"Get ticket","type":"main","index":0}]]}}}