Fixed deprecation warnings for division and darken/lighten

[JorgenSolli]

These deprecation warnings should be fixed:

Deprecation Warning: Using / for division outside of calc() is deprecated and will be removed in Dart Sass 2.0.0.

Deprecation Warning: darken() is deprecated

Deprecation Warning: lighten() is deprecated.

My apologies for not ticking any of the below boxes. I understand if this PR will be ignored. But at least I tried 😄
We're using this library for work, and I don't have time allocated to set up Jasmine, run unit-tests, and provide examples.

Pull Requests

Please accompany all pull requests with the following (where appropriate):

• unit tests (we use Jasmine 2.x.x)
• JSFiddle (or an equivalent such as CodePen, Plunker, etc) or screenshot/GIF with new feature or bug-fix
• Link to original Github issue (if this is a bug-fix)
• documentation updates to README file
• examples within /tpl/index.tpl (for new options being added)
• Passes CI-server checks (runs automated tests, JS source-code linting, etc..). To run these on your local machine, type grunt test in your Terminal within the bootstrap-slider repository directory

[utilmind]

ok

There are another warnings due to scale.color()

[utilmind]

@JorgenSolli unfortunately "build" fails. Is it possible to fix the following warning?
In general I agree, everything make sense, but the following warning should be fixed.

[JorgenSolli]

@JorgenSolli unfortunately "build" fails. Is it possible to fix the following warning? In general I agree, everything make sense, but the following warning should be fixed.

Strange... it's valid syntax according to the SASS documentation.
I tried replicating it in my project, and it compiled fine. The only difference is that I'm using "sass" with Vite, while you're using "grunt-sass". I don't know if that matters, though. It's a bit outside of my technical knowledge.

I'm OK with reverting back to darken() and lighten() for now. Thoughts?

[utilmind]

I'm OK with reverting back to darken() and lighten() for now. Thoughts?

@JorgenSolli I'll check this out later today. In general your improvement is good and make sense to me + I agree that used tools (and probably grunt itself) are outdated. I'll try to build it in different way. If this fails, we'll have to keep darken/lighten.