Added new config option rails_webpacker to better support v4

Webpacker 4 changed default config files babelrc and postcssrc:
rails/webpacker@8d496a0

rails/create-release/README.md

@@ -34,13 +34,16 @@ Those file will be placed relativ to the shared folders and symlinked into the r
 
 Just set this variable in your provisioning/deployment:
 
-```
+```yaml
 rails_webpacker: yes
+
+# if you are using Webpacker 4+, change that to:
+rails_webpacker: 4
 ```
 
 This will:
 
-1. (this role) Export these files from git in addition to the defaults: yarn.lock package.json .babelrc .postcssrc.yml
+1. (this role) Export these files from git in addition to the defaults: yarn.lock package.json .babelrc .postcssrc.yml (babel.config.js and postcss.config.js if using Webpacker 4)
 2. (this role) Keep/Symlink public/packs and node_modules between deployments
 3. (asset precompilation) ``rake yarn:install`` is run by ``rails assets:precompile`` (from +5.1), if a bin/yarn binstub is provided. **NOTE** without that binstub no node_modules are installed! Make sure to add it with ``rails app:update:bin`` and commit to your app repo.
 

rails/create-release/defaults/main.yml

@@ -46,11 +46,15 @@ rails_deploy_custom_create_folders: [] # custom folders that are created for eac
 
 # Webpacker / yarn default settings
 rails_webpacker: no
+
 rails_deploy_webpacker_archive:
 - yarn.lock
 - package.json
-- .babelrc
-- .postcssrc.yml
+- "{% if rails_webpacker_use_webpacker == 4 %}babel.config.js{% else %}.babelrc{% endif %}"
+- "{% if rails_webpacker_use_webpacker == 4 %}postcss.config.js{% else %}.postcssrc.yml{% endif %}"
+
+
+
 
 rails_deploy_webpacker_pack_dir: public/packs
 rails_deploy_custom_shared_webpacker_folders: ['{{rails_deploy_webpacker_pack_dir}}', 'node_modules']