Use compiler_strategy mtime for test environment

It fixes the issue for CI as it's faster than the digest strategy:
https://github.com/shakacode/shakapacker/blob/main/docs/configuration.md#compiler_strategy

.github/workflows/build.yml

@@ -148,7 +148,6 @@ jobs:
       - name: Run tests
 
         env:
-          WEBPACKER_CONFIG: "config/ci_webpacker.yml"
           KNAPSACK_PRO_TEST_SUITE_TOKEN_RSPEC: ff2456e64c9f2aa5157eb0daf711d3c3
           KNAPSACK_PRO_CI_NODE_TOTAL: ${{ matrix.ci_node_total }}
           KNAPSACK_PRO_CI_NODE_INDEX: ${{ matrix.ci_node_index }}

config/ci_webpacker.yml

@@ -1,34 +0,0 @@
-# Note: You must restart bin/webpack-dev-server for changes to take effect
-
-default: &default
-  source_path: app/webpacker
-  source_entry_path: packs
-  public_root_path: public
-  public_output_path: packs
-  cache_path: tmp/cache/webpacker
-  webpack_compile_output: true
-
-  # Additional paths webpack should look up modules
-  # ['app/assets', 'engine/foo/app/assets']
-  additional_paths: [
-    'vendor',
-    'app/webpacker/css',
-    'app/webpacker/fonts',
-    'app/webpacker/images',
-    'engines/web/app/assets/stylesheets',
-    'app/components'
-  ]
-
-  # Reload manifest.json on all requests so we reload latest compiled packs
-  cache_manifest: false
-
-  # Extract and emit a css file
-  extract_css: true
-
-test:
-  <<: *default
-  # Asset are precomiled on CI, so no need to compile here 
-  compile: false 
-
-  # Compile test packs to a separate directory
-  public_output_path: packs-test

config/webpacker.yml

@@ -65,6 +65,7 @@ development:
 test:
   <<: *default
   compile: true
+  compiler_strategy: mtime
 
   # Compile test packs to a separate directory
   public_output_path: packs-test