Tests fail because Sass @import rules have been deprecated

[tiffting]

Tests don't pass locally:

$ script/cibuild
Configuration file: /Users/tiffting/code/jekyll-themes/tactile/_config.yml
 Theme Config file: /Users/tiffting/code/jekyll-themes/tactile/_config.yml
            Source: /Users/tiffting/code/jekyll-themes/tactile
       Destination: /Users/tiffting/code/jekyll-themes/tactile/_site
 Incremental build: disabled. Enable with --incremental
      Generating...
Deprecation Warning [import]: Sass @import rules are deprecated and will be removed in Dart Sass 3.0.0.

More info and automated migrator: https://sass-lang.com/d/import

  ╷
1 │ @import "jekyll-theme-tactile";
  │         ^^^^^^^^^^^^^^^^^^^^^^
  ╵
    /Users/tiffting/code/jekyll-themes/tactile/assets/css/style.scss 1:9  root stylesheet
Deprecation Warning [import]: Sass @import rules are deprecated and will be removed in Dart Sass 3.0.0.

More info and automated migrator: https://sass-lang.com/d/import

  ╷
1 │ @import "rouge-base16-dark";
  │         ^^^^^^^^^^^^^^^^^^^
  ╵
    jekyll-theme-tactile.scss 1:9                                         @import
    /Users/tiffting/code/jekyll-themes/tactile/assets/css/style.scss 1:9  root stylesheet
                    done in 0.776 seconds.
 Auto-regeneration: disabled. Use --watch to enable.
Running ["ImageCheck", "HtmlCheck", "ScriptCheck", "LinkCheck"] on ["./_site"] on *.html...


Checking 3 external links...
Ran on 2 files!


HTML-Proofer finished successfully.
Inspecting 3 files
..W

Offenses:

script/validate-html:24:40: W: [Correctable] Lint/RedundantStringCoercion: Redundant use of Object#to_s in puts.
  results.errors.each { |err| puts err.to_s }
                                       ^^^^

3 files inspected, 1 offense detected, 1 offense autocorrectable
➜  tactile git:(master) npm install -g sass-migrator

added 1 package in 3s