code: public GitlabUser updateUser(Integer targetUserId,
                                   String email, String password, String username,
                                   String fullName, String skypeId, String linkedIn,
                                   String twitter, String website_url, Integer projects_limit,
                                   String extern_uid, String extern_provider_name,
                                   String bio, Boolean isAdmin, Boolean can_create_group, Boolean external) throws IOException {
  
          Query query = new Query()
                  .append("email", email)
                  .appendIf("password", password)
                  .appendIf("username", username)
                  .appendIf("name", fullName)
                  .appendIf("skype", skypeId)
                  .appendIf("linkedin", linkedIn)
                  .appendIf("twitter", twitter)
                  .appendIf("website_url", website_url)
                  .appendIf("projects_limit", projects_limit)
                  .appendIf("extern_uid", extern_uid)
                  .appendIf("provider", extern_provider_name)
                  .appendIf("bio", bio)
                  .appendIf("admin", isAdmin)
                  .appendIf("can_create_group", can_create_group)
                  .appendIf("external", external);
  
          String tailUrl = GitlabUser.USERS_URL + "/" + targetUserId + query.toString();
  
          return retrieve().method(PUT).to(tailUrl, GitlabUser.class);
      }
docs: Update a user
  
  @param targetUserId         User ID
  @param email                User email
  @param password             Password
  @param username             User name
  @param fullName             Full name
  @param skypeId              Skype Id
  @param linkedIn             LinkedIn
  @param twitter              Twitter
  @param website_url          Website URL
  @param projects_limit       Projects limit
  @param extern_uid           External User ID
  @param extern_provider_name External Provider Name
  @param bio                  Bio
  @param isAdmin              Is Admin
  @param can_create_group     Can Create Group
  @param external             External
  @return The Updated User
  @throws IOException on gitlab api call error