Update Gemfile.lock with shakapacker 9.4.0

Syncs Gemfile.lock with the shakapacker 9.4.0 version
specified in Gemfile.development_dependencies.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: justin808

react_on_rails/spec/dummy/Gemfile.lock

@@ -345,7 +345,7 @@ GEM
       rubyzip (>= 1.2.2, < 3.0)
       websocket (~> 1.0)
     semantic_range (3.1.0)
-    shakapacker (9.3.0)
+    shakapacker (9.4.0)
       activesupport (>= 5.2)
       package_json
       rack-proxy (>= 0.6.1)
@@ -461,7 +461,7 @@ DEPENDENCIES
   sass-rails (~> 6.0)
   sdoc
   selenium-webdriver (= 4.9.0)
-  shakapacker (= 9.3.0)
+  shakapacker (= 9.4.0)
   spring (~> 4.0)
   sprockets (~> 4.0)
   sqlite3 (~> 1.6)