Migrate use of @import in scss to @use

[SamuelMiller]

Prerequisites

• I have searched for duplicate or closed feature requests
• I have read the contributing guidelines

Proposal

Currently, Bootstrap scss uses the @import command, which is being phased out according to sass-lang.com

https://sass-lang.com/documentation/at-rules/import
"The Sass team discourages the continued use of the @import rule. Sass will gradually phase it out over the next few years, and eventually remove it from the language entirely. Prefer the @use rule instead. (Note that only Dart Sass currently supports @use. Users of other implementations must use the @import rule instead.)"

They offer a migrator tool, which would make updating the scss files fairly easy: https://sass-lang.com/documentation/cli/migrator

Motivation and context

To keep up with the times, man! :)

[ffoodd]

Duplicates #29853.

On our roadmap for ages, but would be a breaking change in v5. Easy to migrate Bootstrap's core, not really to force a dependency update for millions of users. 😉