Revert "apps: Use source image format for destination"

This reverts commit b877a98.

apps/target_apps_fetcher.py

@@ -183,7 +183,7 @@ def fetch_image(self, target_name: str, arch: str, image: str, dst_root_dir: str
         image_dir = os.path.join(dst_root_dir, uri.host, uri.name, uri.hash)
         os.makedirs(image_dir, exist_ok=True)
         subprocess.check_call(['skopeo', '--insecure-policy', '--override-arch', arch, 'copy',
-                               '--retry-times', '3', '--dest-shared-blob-dir',
+                               '--retry-times', '3', '--format', 'v2s2', '--dest-shared-blob-dir',
                                self.blobs_dir(target_name), 'docker://' + image, 'oci:' + image_dir])
 
         # Store the image manifest in the blob directory, as result it contains all blobs/nodes of