Use sassc-rails instead of sass-rails

Gemfile

@@ -123,7 +123,7 @@ gem 'omniauth'
 gem 'rails', '~> 6.1.7', '>= 6.1.7.10'
 gem 'rails-html-sanitizer', '~> 1.6'
 gem 'rufus-scheduler', '~> 3.9', '>= 3.9.2', require: false
-gem 'sass-rails', '>= 6.0'
+gem 'sassc-rails'
 gem 'select2-rails'
 gem 'spectrum-rails'
 gem 'sprockets'

Gemfile.lock

@@ -737,8 +737,6 @@ GEM
     rubyzip (2.3.2)
     rufus-scheduler (3.9.2)
       fugit (~> 1.1, >= 1.11.1)
-    sass-rails (6.0.0)
-      sassc-rails (~> 2.1, >= 2.1.1)
     sassc (2.4.0)
       ffi (~> 1.9)
     sassc-rails (2.1.2)
@@ -939,7 +937,7 @@ DEPENDENCIES
   rubocop-performance
   rubocop-rspec
   rufus-scheduler (~> 3.9, >= 3.9.2)
-  sass-rails (>= 6.0)
+  sassc-rails
   select2-rails
   selenium-webdriver
   shoulda-matchers