Update links in debian/upstream/metadata

debian/upstream/metadata

-Bug-Database: https://bugs.freedesktop.org/buglist.cgi?bug_status=__open__&content=&product=poppler&query_format=specific&order=bug_id%20DESC&query_based_on=
-Bug-Submit: https://bugs.freedesktop.org/enter_bug.cgi?product=poppler
-Repository: git://git.freedesktop.org/git/poppler/poppler
-Repository-Browse: https://cgit.freedesktop.org/poppler/poppler
+Bug-Database: https://gitlab.freedesktop.org/poppler/poppler/-/issues
+Bug-Submit: https://gitlab.freedesktop.org/poppler/poppler/-/issues/new
+Repository: https://gitlab.freedesktop.org/poppler/poppler.git
+Repository-Browse: https://gitlab.freedesktop.org/poppler/poppler