✨ Add Mailcheck Node (#1690)

* Add Mailcheck integration

* compress logo

* Add mailcheck node info

* ⚡ Improvements

Co-authored-by: bugagashenkj <bugagashenkj@gmail.com>
Co-authored-by: Nosov Konstantin <nosov@nodeart.io>

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

@@ -0,0 +1,18 @@
+import {
+	ICredentialType,
+	NodePropertyTypes,
+} from 'n8n-workflow';
+
+export class MailcheckApi implements ICredentialType {
+	name = 'mailcheckApi';
+	displayName = 'Mailcheck API';
+	documentationUrl = 'mailcheck';
+	properties = [
+		{
+			displayName: 'API Key',
+			name: 'apiKey',
+			type: 'string' as NodePropertyTypes,
+			default: '',
+		},
+	];
+}