Update from shakapacker v6.0.0.rc13 to v6.5.0

Using a two-step process is recommended:
332e25186a/docs/v6_upgrade.md

config/webpack/development.js

@@ -1,5 +0,0 @@
-process.env.NODE_ENV = process.env.NODE_ENV || 'development'
-
-const environment = require('./environment')
-
-module.exports = environment

config/webpack/production.js

@@ -1,5 +0,0 @@
-process.env.NODE_ENV = process.env.NODE_ENV || 'production'
-
-const environment = require('./environment')
-
-module.exports = environment

config/webpack/test.js

@@ -1,5 +0,0 @@
-process.env.NODE_ENV = process.env.NODE_ENV || 'development'
-
-const environment = require('./environment')
-
-module.exports = environment

config/webpacker.yml

@@ -2,11 +2,24 @@
 
 default: &default
   source_path: app/javascript
+
+  # You can have a subdirectory of the source_path, like 'packs' (recommended).
+  # Alternatively, you can use '/' to use the whole source_path directory.
   source_entry_path: /
+
+  # If nested_entries is true, then we'll pick up subdirectories within the source_entry_path.
+  # You cannot set this option to true if you set source_entry_path to '/'
+  nested_entries: false
+
   public_root_path: public
   public_output_path: packs
   cache_path: tmp/webpacker
   webpack_compile_output: true
+  # See https://github.com/shakacode/shakapacker#deployment
+  webpacker_precompile: true
+
+  # Location for manifest.json, defaults to {public_output_path}/manifest.json if unset
+  # manifest_path: public/packs/manifest.json
 
   # Additional paths webpack should look up modules
   # ['app/assets', 'engine/foo/app/assets']
@@ -15,9 +28,19 @@ default: &default
   # Reload manifest.json on all requests so we reload latest compiled packs
   cache_manifest: false
 
+  # Select loader to use, available options are 'babel' (default), 'swc' or 'esbuild'
+  webpack_loader: 'babel'
+
+  # Set to true to enable check for matching versions of shakapacker gem and NPM package - will raise an error if there is a mismatch or wildcard versioning is used
+  ensure_consistent_versioning: true
+
+  # Select whether the compiler will use SHA digest ('digest' option) or most most recent modified timestamp ('mtime') to determine freshness
+  compiler_strategy: digest
+
 development:
   <<: *default
   compile: true
+  compiler_strategy: mtime
 
   # Reference: https://webpack.js.org/configuration/dev-server/
   dev_server:
@@ -26,6 +49,14 @@ development:
     port: 3035
     # Hot Module Replacement updates modules while the application is running without a full reload
     hmr: false
+    # If HMR is on, CSS will by inlined by delivering it as part of the script payload via style-loader. Be sure
+    # that you add style-loader to your project dependencies.
+    #
+    # If you want to instead deliver CSS via <link> with the mini-extract-css-plugin, set inline_css to false.
+    # In that case, style-loader is not needed as a dependency.
+    #
+    # mini-extract-css-plugin is a required dependency in both cases.
+    inline_css: true
     # Defaults to the inverse of hmr. Uncomment to manually set this.
     # live_reload: true
     client: