images: Use crane for pushing release images instead of docker

Currently, we're loading the images into docker, retagging them, and
then push them onto the registry.

This workflow is incompatible with Windows images, as docker load does
not work for them, resulting in the following error:

cannot load windows image on linux

However, crane does not load the image, it just pushes it directly with
the given tag. This will allow us to push any Windows image we might have
(e.g.: Windows kube-proxy image).

push-build.sh

@@ -1348,6 +1348,16 @@ release::gcs::publish () {
   fi
 }
 
+ensure_crane_exists () {
+  if ! command -v crane &> /dev/null; then
+    echo "Installing crane..."
+    CRANE_VERSION="v0.19.0"
+    curl -sL "https://github.com/google/go-containerregistry/releases/download/${CRANE_VERSION}/go-containerregistry_Linux_x86_64.tar.gz" > go-containerregistry.tar.gz
+    sudo tar -zxvf go-containerregistry.tar.gz -C /usr/local/bin/ crane
+    rm go-containerregistry.tar.gz
+  fi
+}
+
 ###############################################################################
 # Releases all docker images to a docker registry using the docker tarfiles.
 #
@@ -1370,6 +1380,8 @@ release::docker::release () {
 
   common::argc_validate 3
 
+  ensure_crane_exists
+
   logecho "Send docker containers from release-images to $push_registry..."
 
   mapfile -t arches < <(find "${release_images}" -maxdepth 1 -mindepth 1 -type d -exec basename {} \;)
@@ -1388,16 +1400,10 @@ release::docker::release () {
       new_tag_with_arch=("$new_tag-$arch:$version")
       manifest_images["${new_tag}"]+=" $arch"
 
-      logrun docker load -qi $tarfile
-      logrun docker tag $orig_tag ${new_tag_with_arch}
       logecho -n "Pushing ${new_tag_with_arch}: "
-      # TODO: Use docker direct when fixed later
-      #logrun -r 5 -s docker push "${new_tag_with_arch}" || return 1
-      logrun -r 5 -s $GCLOUD docker -- push "${new_tag_with_arch}" || return 1
-      if [[ "${PURGE_IMAGES:-yes}" == "yes" ]] ; then
-        logrun docker rmi $orig_tag ${new_tag_with_arch} || true
-      fi
-
+      # We don't need to load the image when pushing it with crane.
+      # This will also allow us to push any Windows images we might have.
+      logrun -r 5 -s $GCLOUD crane push $tarfile "${new_tag_with_arch}" || return 1
     done
   done