Fix script/convert for new monorepo structure

Update Gemfile.development_dependencies path to point to the new location
under react_on_rails/ directory after the monorepo restructuring.

Changes:
- ../Gemfile.development_dependencies → ../react_on_rails/Gemfile.development_dependencies

Fixes CI error:
- No such file or directory - react_on_rails_pro/Gemfile.development_dependencies

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

Co-Authored-By: Claude <[email protected]>

Author: justin808

script/convert

@@ -18,7 +18,7 @@ end
 # move("../react_on_rails/spec/dummy/config/shakapacker.yml", "../react_on_rails/spec/dummy/config/webpacker.yml")
 
 # Shakapacker - use version with async script loading support (8.2.0+)
-gsub_file_content("../Gemfile.development_dependencies", /gem "shakapacker", "[^"]*"/, 'gem "shakapacker", "8.2.0"')
+gsub_file_content("../react_on_rails/Gemfile.development_dependencies", /gem "shakapacker", "[^"]*"/, 'gem "shakapacker", "8.2.0"')
 gsub_file_content("../react_on_rails/spec/dummy/package.json", /"shakapacker": "[^"]*",/, '"shakapacker": "8.2.0",')
 
 # The below packages don't work on the oldest supported Node version and aren't needed there anyway