Malformed YAML after symfony/yaml update

Hi,

I'm working with a Drupal 9.1 rc3 site, and there was a recent update to symfony/yaml that caused the libraries.yml file in this module to be malformed, causing the site to get the unexpected error screen. I've attached the .yml file here so that it can be committed.

I'm also a maintainer on the Simple Popup Blocks module:

https://www.drupal.org/project/simple_popup_blocks →

I've fixed the issue for that module, and am willing to do the same for this module if given permission.

Thanks,
Matt