Update gettextpo website and repository URLs.

Author: gemmaro

gettextpo.gem

@@ -1,8 +1,8 @@
 name: gettextpo
 description: GNU gettext PO parser library with libgettextpo.
 author: gemmaro
-website: https://git.disroot.org/gemmaro/ruby-gettextpo
+website: https://github.com/ruby-gettext/gettextpo
 protocol: git
-repository: https://git.disroot.org/gemmaro/ruby-gettextpo.git
+repository: https://github.com/ruby-gettext/gettextpo
 license: GPL-3.0-or-later
 branch: main