code: public Pager<User> findUsers(String emailOrUsername, int itemsPerPage) throws GitLabApiException {
          GitLabApiForm formData = createGitLabApiForm().withParam("search", emailOrUsername, true);
          return (new Pager<User>(this, User.class, itemsPerPage, formData.asMap(), "users"));
      }
docs: Search users by Email or username and return a Pager
  
  <pre><code>GitLab Endpoint: GET /users?search=:email_or_username</code></pre>
  
  @param emailOrUsername the email or username to search for
  @param itemsPerPage    the number of Project instances that will be fetched per page
  @return the User Pager with the email or username like emailOrUsername
  @throws GitLabApiException if any exception occurs