use perl-releases page instead of scraping search.cpan.org

I made perl-releases page (http://perl-releases.s3-website-us-east-1.amazonaws.com/)
This page is generated by https://github.com/kazeburo/perl-releases-list and hosted on Amazon S3.

In perl_release(), use this perl-release page instead of accessing to search.cpan.org. It's lighter than scraping search.cpan.org and has high availability.