encoding issues on MSWin32

[karenetheridge]

here's an example test: http://www.cpantesters.org/cpan/report/12ed2af8-6bf4-1014-8695-9e662ad63fef

the test: https://metacpan.org/source/ETHER/Dist-Zilla-Plugin-Git-Contributors-0.004/t/01-basic.t#L50 and the prep work done for MSWin32: https://metacpan.org/source/ETHER/Dist-Zilla-Plugin-Git-Contributors-0.004/t/lib/GitSetup.pm#L37

sadly, this doesn't seem to be enough. But I'm not sure what's missing.