Update mini_racer requirement from ~> 0.8.0 to ~> 0.14.1

Updates the requirements on [mini_racer](https://github.com/discourse/mini_racer) to permit the latest version.
- [Changelog](https://github.com/rubyjs/mini_racer/blob/main/CHANGELOG)
- [Commits](rubyjs/mini_racer@v0.8.0...v0.14.1)

---
updated-dependencies:
- dependency-name: mini_racer
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile

@@ -15,7 +15,7 @@ gem "sass-rails", "~> 6.0.0"
 # Use Uglifier as compressor for JavaScript assets
 gem "uglifier", ">= 4.2.0"
 # See https://github.com/rails/execjs#readme for more supported runtimes
-gem 'mini_racer', '~> 0.8.0'
+gem 'mini_racer', '~> 0.14.1'
 
 # Use CoffeeScript for .coffee assets and views
 gem "coffee-rails", "~> 5.0.0"