✨ Gmail node (#856)

* ✨ Gmail node

* ⚡ Improvements

* ⚡ Improvements

* ⚡ Improvements to Gmail-Node

* ⚡ Additional improvements to Gmail-Node

Co-authored-by: Erin <erin2722@gmail.com>
Co-authored-by: ricardo <ricardoespinoza105@gmail.com>

packages/nodes-base/credentials/GmailOAuth2Api.credentials.ts

@@ -0,0 +1,30 @@
+import {
+	ICredentialType,
+	NodePropertyTypes,
+} from 'n8n-workflow';
+
+const scopes = [
+	'https://www.googleapis.com/auth/gmail.labels',
+	'https://www.googleapis.com/auth/gmail.addons.current.action.compose',
+	'https://www.googleapis.com/auth/gmail.addons.current.message.action',
+	'https://mail.google.com/',
+	'https://www.googleapis.com/auth/gmail.modify',
+	'https://www.googleapis.com/auth/gmail.compose',
+];
+
+
+export class GmailOAuth2Api implements ICredentialType {
+	name = 'gmailOAuth2';
+	extends = [
+		'googleOAuth2Api',
+	];
+	displayName = 'Gmail OAuth2 API';
+	properties = [
+		{
+			displayName: 'Scope',
+			name: 'scope',
+			type: 'hidden' as NodePropertyTypes,
+			default: scopes.join(' '),
+		},
+	];
+}