[build] npm run setup didn't run on windows

[cyantree]

When running npm run setup on windows (without WSL) it fails with the following message:

node:internal/validators:162
    throw new ERR_INVALID_ARG_TYPE(name, 'string', value);
          ^

TypeError [ERR_INVALID_ARG_TYPE]: The "path" argument must be of type string. Received undefined
    at validateString (node:internal/validators:162:11)
    at Object.basename (node:path:756:5)
    at transformFileName (scripts\build\generate-css.ts:13:15)
    at generateCoreCSS (\scripts\build\generate-css.ts:57:56) {
  code: 'ERR_INVALID_ARG_TYPE'
}

This is because of the glob path containing back slashes but fast-glob not supporting these:
https://www.npmjs.com/package/fast-glob#pattern-syntax

Always use forward-slashes in glob expressions (patterns and ignore option).

[rtivital]

Thanks!