docs: public AuthConfig createAuthConfig(boolean isPush, boolean skipExtendedAuth, Map authConfig, Settings settings, String user, String registry)
              throws MojoExecutionException {
  
          AuthConfig ret = createStandardAuthConfig(isPush, authConfig, settings, user, registry);
          if (ret != null) {
              if (registry == null || skipExtendedAuth) {
                  return ret;
              }
              try {
                  return extendedAuthentication(ret, registry);
              } catch (IOException e) {
                  throw new MojoExecutionException(e.getMessage(), e);
              }
          }
  
          // Finally check ~/.docker/config.json
          ret = getAuthConfigFromDockerConfig(registry);
          if (ret != null) {
              log.debug("AuthConfig: credentials from ~/.docker/config.json");
              return ret;
          }
  
          log.debug("AuthConfig: no credentials found");
          return null;
      }