How to update the version of AngularJS using module configuration
As @Jimmy Ko suggested I have fixed the issue as follows:

I have added the following code in the function angularjs_version_files() of file sites\all\modules\angularjs\angularjs.module. Then selected the AngularJS version 1.5.8 in admin/config/development/angularjs.

$files['1.5.8'] = array(
    'angular-animate',
    'angular-aria',
    'angular-cookies',
    'angular-loader',
    'angular-messages',
    'angular-mocks',
    'angular-resource',
    'angular-route',
    'angular-sanitize',
    'angular-scenario',
    'angular-touch'
  );


Now, in the view source I can see the latest AngularJS file is included in my project.