Retry skopeo inspect command

Enables to retry skopeo inspect. Add `--retry-times` to set the number of times to retry. Use exponential backoff and  1s as default initial retry delay.

Signed-off-by: Qi Wang <qiwan@redhat.com>

completions/bash/skopeo

@@ -73,6 +73,7 @@ _skopeo_inspect() {
      --authfile
      --creds
      --cert-dir
+     --retry-times
      "
      local boolean_options="
      --config