sass-loader v8+ compatibility #587

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Bug report

Including sass files while using sass-loader version 8+ throws error when compiling the app

ValidationError: Invalid options object. Sass Loader has been initialised using an options object that does not match the API schema. - options has an unknown property 'indentedSyntax'. These properties are valid: object { implementation?, sassOptions?, prependData?, sourceMap?, webpackImporter? } at validate

Reason is sass-loader introduced breaking change in 8.0 moving all sass options under sassOptions sub-key

Problematic file is config-css.js

Fix will be probably hard without introducing incompatibility with previous versions of sass-loader. Are you sure this option is actually necessary ? My understanding is both node-sass and dart-sass are able to switch between syntax based on file extension - indented for sass and non-indented for scss

Other problem I see is that in saber-config the build.loaderOptions.sass is used for both sass and scss configuration. It would be useful to have dedicated key just for scss

Steps to reproduce

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What is expected?

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