fix(Ghost Node): Fix post tags and add credential tests (#3278)

* Renamed Tag IDs to Tags and changed the value to tag.name

* Updated credentials to use new system

* Nodelinter changes

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

@@ -1,5 +1,8 @@
 import {
+	ICredentialDataDecryptedObject,
+	ICredentialTestRequest,
 	ICredentialType,
+	IHttpRequestOptions,
 	INodeProperties,
 } from 'n8n-workflow';
 
@@ -22,4 +25,18 @@ export class GhostContentApi implements ICredentialType {
 			default: '',
 		},
 	];
+	async authenticate(credentials: ICredentialDataDecryptedObject, requestOptions: IHttpRequestOptions): Promise<IHttpRequestOptions> {
+		requestOptions.qs = {
+			...requestOptions.qs,
+			'key': credentials.apiKey,
+		};
+		return requestOptions;
+	}
+	test: ICredentialTestRequest = {
+		request: {
+			baseURL: '={{$credentials.url}}',
+			url: '/ghost/api/v3/content/settings/',
+			method: 'GET',
+		},
+	};
 }