style: use single-quoted require in e2e template

Author: justin808

packages/shakacode_demo_common/lib/generators/shakacode_demo_common/install/templates/e2e.rake

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative "../../../../packages/shakacode_demo_common/lib/shakacode_demo_common/e2e_test_runner"
+require_relative '../../../../packages/shakacode_demo_common/lib/shakacode_demo_common/e2e_test_runner'
 
 namespace :e2e do
   desc 'Run Playwright tests against all dev modes (bin/dev, bin/dev static, bin/dev prod)'