add basic customer.io trigger

packages/nodes-base/credentials/CustomerIoApi.credentials.ts

@@ -0,0 +1,19 @@
+import {
+	ICredentialType,
+	NodePropertyTypes,
+} from 'n8n-workflow';
+
+
+export class CustomerIoApi implements ICredentialType {
+	name = 'customerIoApi';
+	displayName = 'Customer.io API';
+	properties = [
+		{
+			displayName: 'API Key',
+			name: 'apiKey',
+			type: 'string' as NodePropertyTypes,
+			default: '',
+		},
+
+	];
+}