Chore: Add method to get a discussion using a number/id

src/main/java/org/kohsuke/github/GHTeam.java

@@ -147,6 +147,25 @@ public class GHTeam extends GHObject implements Refreshable {
         });
     }
 
+    /**
+     * Gets a single discussion by ID.
+     *
+     * @param discussionId
+     *            id of the discussion that we want to query for
+     * @return the discussion
+     * @throws IOException
+     *             the io exception
+     *
+     * @see <a href= "https://developer.github.com/v3/teams/discussions/#get-a-discussion">documentation</a>
+     */
+    public GHDiscussion getDiscussion(String discussionId) throws IOException {
+        return root.createRequest()
+                .withUrlPath("/orgs/" + this.getOrganization().getLogin() + "/teams/" + this.getSlug() + "/discussions/"
+                        + discussionId)
+                .fetch(GHDiscussion.class)
+                .wrapUp(this);
+    }
+
     /**
      * Retrieves the current members.
      *