Make `sass` a peerDependency

[Richienb]

Instead of manually updating the sass dependency every time an update is available, it could be done by the consumer instead.

[tgrassl]

This would be really helpful for us as well 👍

[sommereder]

+100

[rwaskiewicz]

Hey folks,

Thanks for the patience on this one. After doing a little digging and discussing with the team, we've come to consensus that making sass a peer dependency is not something we feel is the right decision for this library.

This decision is influenced by the following points:

• We believe that making sass a peer dependency will increase the difficulty in maintaining this library. The points below can lead to incompatibilities between this library and sass (increasing maintenance burden):
  • sass can have breaking changes in minor versions, often called "maybe breaking changes" (reference)
  • The Sass 1.55 upgrade breaks the development cycle of @stencil/sass, as typings provided by Sass change in ways that cause build failures
• We control the version of sass used today, which simplifies our support matrix of this library and sass
• While we could make sass a peer-dependency, we believe we would need to make that peer-dependency rather restrictive, which we believe creates a compromise where nobody is quite pleased with the outcome.

I'm going to be scheduling https://github.com/ionic-team/stencil-sass/pull/157 to be completed in the near future, so that we can support a newer version of Sass.

Thanks!