feat: add method to fetch merge request discussions

src/api.ts

@@ -17,6 +17,7 @@ import * as request from 'request-promise-native';
 import {
   AccessLevel,
   Branch,
+  Discussion,
   Group,
   Issue,
   IssueState,
@@ -367,6 +368,18 @@ export class Api {
     return this.makeGitLabAPIRequest(`/projects/${projectId}/merge_requests/${mergeRequestIid}/approvals`);
   }
 
+  /**
+   * Get discussions of a merge request
+   *
+   * @param projectId ID of the project the merge request belongs to
+   * @param mergeRequestIid IID of the merge request
+   */
+  public getMergeRequestDiscussions(projectId: number, mergeRequestIid: number): Promise<Discussion> {
+    return this.makeGitLabAPIRequest(
+      `projects/${projectId}/merge_requests/${mergeRequestIid}/discussions`,
+    );
+  }
+
   /**
    * Get merge requests of a group or a project
    *