Add rubygem-gpgme 2.0.13

Ruby-GPGME is a Ruby language binding of GPGME (GnuPG Made Easy). GnuPG Made
Easy (GPGME) is a library designed to make access to GnuPG easier for
applications. It provides a High-Level Crypto API for encryption, decryption,
signing, signature verification and key management.

WWW: https://github.com/ueno/ruby-gpgme