_redirects: Add .sig and .sha256sum for redirection as well
requested to merge mvlad/wayland.freedesktop.org:wip/mvlad/remove-older-tarballs-sig-sha256sum into main
Missed out the .sig and .sham256sum files, only added for the tarballs.
This adds those as well.
Signed-off-by: Marius Vlad marius.vlad@collabora.com