code: public ExternalWikiService updateExternalWikiService(Object projectIdOrPath,  ExternalWikiService externalWiki) throws GitLabApiException {
          GitLabApiForm formData = new GitLabApiForm()
                  .withParam("external_wiki_url", externalWiki.getExternalWikiUrl());
          Response response = put(Response.Status.OK, formData.asMap(), "projects", getProjectIdOrPath(projectIdOrPath), "services", "external-wiki");
          return (response.readEntity(ExternalWikiService.class));
      }
docs: Updates the ExternalWikiService service settings for a project.
  
  <pre><code>GitLab Endpoint: PUT /projects/:id/services/external-wiki</code></pre>
  
  The following properties on the JiraService instance are utilized in the update of the settings:
  <p>
  external_wiki_url (required) - The URL to the External Wiki project which is being linked to this GitLab project, e.g., http://www.wikidot.com/
  
  @param projectIdOrPath id, path of the project, or a Project instance holding the project ID or path
  @param externalWiki            the ExternalWikiService instance holding the settings
  @return a ExternalWikiService instance holding the newly updated settings
  @throws GitLabApiException if any exception occurs