fix plugin specification

I tried to do some experiments with Mock::Person dist, but I got an error:

    sromanov@snapdozer:~/mydev/Mock-Person$ dzil build
    Can't locate Dist/Zilla/Plugin/Dist/Zilla/Plugin/Test/CPAN/Changes.pm in @INC (you may need to install the Dist::Zilla::Plugin::Dist::Zilla::Plugin::Test::CPAN::Changes module) (@INC contains: /home/sromanov/perl5/perlbrew/perls/perl-blead/lib/site_perl/5.19.3/i686-linux /home/sromanov/perl5/perlbrew/perls/perl-blead/lib/site_perl/5.19.3 /home/sromanov/perl5/perlbrew/perls/perl-blead/lib/5.19.3/i686-linux /home/sromanov/perl5/perlbrew/perls/perl-blead/lib/5.19.3 .) at /home/sromanov/perl5/perlbrew/perls/perl-blead/lib/site_perl/5.19.3/Module/Runtime.pm line 317, <GEN1> line 11. at /home/sromanov/perl5/perlbrew/perls/perl-blead/lib/site_perl/5.19.3/Config/MVP/Assembler.pm line 87.

I fixed the `D::Z::P::Test::CPAN::Changes` plugin specification in your plugin list.