Downgrade sass version to avoid deprecation errors from ui-kit

[rpocklin]

Description

I'm upgrading our version of owncloud/web to use v9.0.0 of the owncloud-design-system and there are many deprecation warnings in ui-kit, any thoughts on this? Downgrading to sass v1.32.12 removes the warnings and makes it easier to digest the console log and any actual errors that may occur.

⠼ Building Design System...DEPRECATION WARNING: Using / for division is deprecated and will be removed in Dart Sass 2.0.0.
Recommendation: math.div($global-gutter, 2)
247 │ $card-header-padding-vertical: round($global-gutter / 2) !default;
    │                                      ^^^^^^^^^^^^^^^^^^
    ╵
    node_modules/uikit/src/scss/variables-theme.scss 247:38  @import
    src/styles/styles.scss 187:9                             root stylesheet```

## How Has This Been Tested?
Built with `yarn build:system` and compared binaries, there is no binary difference using Node.js v14.15.0

[update-docs]

Thanks for opening this pull request! The maintainers of this repository would appreciate it if you would create a changelog item based on your changes.

[CLAassistant]

All committers have signed the CLA.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

81.1% Coverage
3.0% Duplication