Revert "Use buildah's built-in checksumming"

This reverts commit 231ff05.

Buildah's checksum functionality is removed by a patch in the
Ubuntu 24.04 GitHub Actions runner

Containerfile

@@ -1,3 +1,8 @@
+FROM quay.io/fedora-ostree-desktops/silverblue:40 as docker-desktop-rpm 
+COPY checksums checksums
+ADD https://desktop.docker.com/linux/main/amd64/160616/docker-desktop-x86_64.rpm docker-desktop-x86_64.rpm 
+RUN sha256sum -c checksums
+
 FROM quay.io/fedora-ostree-desktops/silverblue:40 as silverblue
 
 COPY docker-ce.repo /etc/yum.repos.d/docker-ce.repo
@@ -10,10 +15,7 @@ RUN rpm-ostree ex rebuild \
 # Copying this pattern from here https://github.com/coreos/rpm-ostree/issues/233#issuecomment-1301194050
 # There have been updates since this was written in Nov 2022 but as of July 2024, this is still the 
 # recommended way https://github.com/coreos/fedora-coreos-tracker/issues/1681#issuecomment-2211137520 
-ARG docker_desktop_build_number=160616
-ADD --checksum=sha256:ba644d1ec8749e50863badf56620c453544b82f917ac13eb03f8c5c105825fb4 \
-    https://desktop.docker.com/linux/main/amd64/${docker_desktop_build_number}/docker-desktop-x86_64.rpm \
-    docker-desktop-x86_64.rpm 
+COPY --from=docker-desktop-rpm docker-desktop-x86_64.rpm docker-desktop-x86_64.rpm
 RUN mkdir /var/opt \
     && rpm -Uvh docker-desktop-x86_64.rpm \
     && mv /var/opt/docker-desktop /usr/lib/opt/docker-desktop \

checksums

@@ -0,0 +1 @@
+ba644d1ec8749e50863badf56620c453544b82f917ac13eb03f8c5c105825fb4	docker-desktop-x86_64.rpm