Update flatpak manifest

Summary:
We require newer KF5 and Qt than the 5.9 runtime provides. Update to 5.13.
libarchive 3.2 seems to miss zstd support. Update to 3.4

Test Plan: flatpak builds

Reviewers: Ark, apol, elvisangelaccio

Reviewed By: Ark, apol, elvisangelaccio

Subscribers: elvisangelaccio, kde-utils-devel

Tags: Ark

Differential Revision: https://phabricator.kde.org/D25847