Replace SCSS Lint with Stylelint

scss-lint-govuk has been deprecated and is superseded by stylelint-config-gds

Gemfile

@@ -83,7 +83,6 @@ group :development do
   gem "rubocop-govuk", require: false
   gem "rubocop-performance", require: false
   gem "rubocop-rails", require: false
-  gem "scss_lint-govuk"
 end
 
 group :test do

Gemfile.lock

@@ -410,15 +410,6 @@ GEM
     ruby-progressbar (1.11.0)
     ruby2_keywords (0.0.5)
     rubyzip (2.3.2)
-    sass (3.7.4)
-      sass-listen (~> 4.0.0)
-    sass-listen (4.0.0)
-      rb-fsevent (~> 0.9, >= 0.9.4)
-      rb-inotify (~> 0.9, >= 0.9.7)
-    scss_lint (0.59.0)
-      sass (~> 3.5, >= 3.5.5)
-    scss_lint-govuk (0.2.0)
-      scss_lint
     selenium-webdriver (4.1.0)
       childprocess (>= 0.5, < 5.0)
       rexml (~> 3.2, >= 3.2.5)
@@ -514,7 +505,6 @@ DEPENDENCIES
   rubocop-govuk
   rubocop-performance
   rubocop-rails
-  scss_lint-govuk
   selenium-webdriver
   sentry-rails
   sentry-ruby

package.json

@@ -37,7 +37,9 @@
   },
   "version": "0.1.0",
   "devDependencies": {
-    "are-you-es5": "^2.1.2"
+    "are-you-es5": "^2.1.2",
+    "stylelint": "^14.7.1",
+    "stylelint-config-gds": "^0.2.0"
   },
   "browserslist": {
     "production": [
@@ -51,6 +53,9 @@
       "last 1 safari version"
     ]
   },
+  "stylelint": {
+    "extends": "stylelint-config-gds/scss"
+  },
   "scripts": {
     "build": "webpack --config webpack.config.js"
   }