path to the css theme files is incorrect

Problem/Motivation

Smartmenus CSS is not loading properly.

Proposed resolution

in smartmenus.libraries.yml the path to the css theme files is incorrect. the four style themes are now in their own folders.
Lines 9-14 currently:

css:
    theme:
      /libraries/smartmenus/css/sm-blue.css: {}
      /libraries/smartmenus/css/sm-clean.css: {}
      /libraries/smartmenus/css/sm-mint.css: {}
      /libraries/smartmenus/css/sm-simple.css: {}

Lines 9-14 corrected:

css:
    theme:
      /libraries/smartmenus/css/sm-blue/sm-blue.css: {}
      /libraries/smartmenus/css/sm-clean/sm-clean.css: {}
      /libraries/smartmenus/css/sm-mint/sm-mint.css: {}
      /libraries/smartmenus/css/sm-simple/sm-simple.css: {}

Line 15 for sm-core-css.css does not need to change, as it is not in a subfolder:
/libraries/smartmenus/css/sm-core-css.css: {}

Remaining tasks

By editing the yml file, the included theme styles are now loading properly.