Gtk3 dist.ini changes to add/update project metadata

[Brian Manning <cpan xaoc org>]

Hi all,

Neil Bowers sent me a Git pull request against my personal copy of
Gtk3 on GitHub to add the [GithubMeta] plugin to dist.ini.  I
documented this in RT#89118 [1].

I ended up using the [MetaResources] plugin in dist.ini instead of
[GithubMeta], because [MetaResources] lets me specify all of the
"official" URLs for the project, whereas [GithubMeta] would have used
my personal copy of Gtk3, which is far, far, far from "official"

I also have another change to add the [MetaJSON] plugin to dist.ini,
and added a 'version = 2' param to the existing [MetaYAML] plugin,
which will update all of the metadata files that ship with Gtk3 and
give us the nice URLs in MetaCPAN.

There's one other change that I made, there's a Dist::Zilla parameter
called 'is_testing' that you can use to set the 'testing' flag in
META.[yml|json].  I currently have it commented out, along with a note
that explains what the parameter is for.

Torsten, would it be worth it to enable this 'is_testing' flag for
Gtk3, or is it already understood that Gtk3 is beta software?  I'm not
sure what this flag will do to CPAN/MetaCPAN as far as search results
for Gtk3, i.e. this flag may cause CPAN/MetaCPAN to hide releases with
this flag set.

You can view my changes at [2].  If nobody has any complaints, I'll
push them over to git.gnome.org after a week or so.

Thanks again to Neil for the original Git pull request.

Thanks,

Brian

[1] https://rt.cpan.org/Public/Bug/Display.html?id=89118
[2] https://github.com/cpanxaoc/perl-Gtk3/commits/master