package/skopeo: bump to 1.20.0
In 1.20.0, skopeo gained a new optional dependency on sqlite, so enable
that when available, and use that in the runtime tests.
Changes since 1.18.0:
https://github.com/containers/skopeo/releases/tag/v1.19.0
https://github.com/containers/skopeo/releases/tag/v1.20.0
Signed-off-by: Yann E. MORIN <yann.morin@orange.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>