feat(core): Add "Client Credentials" grant type to OAuth2 (#3489)

* ⚡ Add OAuth2 client credentials grant type

* ⚡ Improvements

* 🐛 Fix linting issue

* 🐛 Fix typo

* 🐛 Fix small issue with type

* 🐛 When token expire get a new one instead of refreshing it

* ⚡ Fix issue that it did not display it correctly for OAuth1

Co-authored-by: Jan Oberhauser <jan.oberhauser@gmail.com>

packages/nodes-base/credentials/GithubOAuth2Api.credentials.ts

@@ -12,6 +12,12 @@ export class GithubOAuth2Api implements ICredentialType {
 	displayName = 'GitHub OAuth2 API';
 	documentationUrl = 'github';
 	properties: INodeProperties[] = [
+		{
+			displayName: 'Grant Type',
+			name: 'grantType',
+			type: 'hidden',
+			default: 'authorizationCode',
+		},
 		{
 			displayName: 'Github Server',
 			name: 'server',