drop support for webpacker 3

Author: Judahmeek

Appraisals

@@ -14,13 +14,6 @@ appraise 'rails-5.2-sprockets_3' do
   gem 'therubyrhino', :platforms => :jruby
 end
 
-appraise 'rails-5.2_no_sprockets_webpacker_3' do
-  gem 'rails', '~> 5.2.x'
-  gem 'webpacker', '~> 3.0'
-  gem 'mini_racer', :platforms => :mri
-  gem 'therubyrhino', :platforms => :jruby
-end
-
 appraise 'rails-5.2_no_sprockets_webpacker_4' do
   gem 'rails', '~> 5.2.x'
   gem 'webpacker', '~> 4.0'

gemfiles/rails_5.2_no_sprockets_webpacker_3.gemfile

@@ -103,10 +103,8 @@ def assets_precompiled?
       def asset_container_class
         if self.class.asset_container_class.present?
           self.class.asset_container_class
-        elsif SeparateServerBundleContainer.compatible? && self.class.dont_use_webpacker_manifest
+        elsif SeparateServerBundleContainer.compatible?
           SeparateServerBundleContainer
-        elsif WebpackerManifestContainer.compatible?
-          WebpackerManifestContainer
         elsif assets_precompiled?
           if ManifestContainer.compatible?
             ManifestContainer

gemfiles/rails_5.2_no_sprockets_webpacker_3.gemfile.lock

@@ -1,6 +1,6 @@
 {
   "dependencies": {
-    "@rails/webpacker": "^3.0.1",
+    "@rails/webpacker": "^4.0.0",
     "babel-preset-react": "^6.24.1",
     "create-react-class": "^15.6.2",
     "prop-types": "^15.6.0",