function testGhPagesLocally(isBeta) {
  return gulp.series(
    gulp.parallel(
      preparePluginsForLocal(isBeta),
      prepareExamplesForLocal(isBeta),
    ),
    predeployTasks.predeployAllLocal,
    function (done) {
      console.log('Starting server using http-server');
      execSync(`npx http-server`, {cwd: 'gh-pages', stdio: 'inherit'});
      done();
    },
  );
}
Does all the necessary tasks to run github pages locally.
@param {boolean} isBeta True if we want to test gh pages with the beta
    version of Blockly. This is particularly helpful for testing before we
    release core.
@returns {Function} Gulp task.