move rootless-cni-infra image to quay.io

Move the `rootless-cni-infra` image to `quay.io/libpod/rootless-cni-image:$tag`
where $tag has the format `$version-$architecture`.  Whenever we upload
a new image (e.g., after changing the Containerfile), we need to make
sure to increase the version number (an ordinary integer for simplicity) so we
have a notion of support.

Thanks to @AkihiroSuda for working on rootless CNI!

Fixes: #7617
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

contrib/rootless-cni-infra/Containerfile

@@ -33,3 +33,5 @@ COPY --from=dnsname /dnsname /opt/cni/bin
 COPY rootless-cni-infra /usr/local/bin
 ENV CNI_PATH=/opt/cni/bin
 CMD ["sleep", "infinity"]
+
+ENV ROOTLESS_CNI_INFRA_VERSION=1

contrib/rootless-cni-infra/README.md

@@ -16,6 +16,8 @@ Podman then allocates a CNI netns in the infra container, by executing an equiva
 The allocated netns is deallocated when the container is being removed, by executing an equivalent of:
 `podman exec rootless-cni-infra rootless-cni-infra dealloc $CONTAINER_ID $NETWORK_NAME`.
 
+The container images live on `quay.io/libpod/rootless-cni-infra`.  The tags have the format `$version-$architecture`.  Please make sure to increase the version number in the Containerfile (i.e., `ROOTLESS_CNI_INFRA_VERSION`) when applying changes to this directory.  After committing the changes, upload the image(s) with the corresponding tag.
+
 ## Directory layout
 
 * `/run/rootless-cni-infra/${CONTAINER_ID}/pid`: PID of the `sleep infinity` process that corresponds to the allocated netns

contrib/rootless-cni-infra/rootless-cni-infra

@@ -2,7 +2,6 @@
 set -eu
 
 ARG0="$0"
-VERSION="0.1.0"
 BASE="/run/rootless-cni-infra"
 
 # CLI subcommand: "alloc $CONTAINER_ID $NETWORK_NAME $POD_NAME"
@@ -126,7 +125,7 @@ cmd_entrypoint_help() {
 
 # CLI subcommand: "version"
 cmd_entrypoint_version() {
-	echo "{\"version\": \"${VERSION}\"}"
+	echo "{\"version\": \"${ROOTLESS_CNI_INFRA_VERSION}\"}"
 }
 
 # parse args