code: public static Map<String, Object> createProxyClientConfig(String proxyUri) {
          return (createProxyClientConfig(proxyUri, null, null));
      }
docs: Create a Map instance with properties set up to use a proxy server that can be passed to the
  GitLabAPi constructors and login methods to configure the GitLabApi instance to use a proxy server.
  
  @param proxyUri the URI of the proxy server
  @return a Map set up to allow GitLabApi to use a proxy server