Handle missing 'path' library dependency

Require path instead of assuming it's already imported.

Author: justin808

lib/generators/react_on_rails/dev_tests_generator.rb

@@ -41,7 +41,7 @@ def change_webpack_client_base_config_to_include_fallback
   // This fixes an issue with resolving 'react' when using a local symlinked version
   // of the node_package folder
   resolveLoader: {
-    fallback: [path.join(__dirname, 'node_modules')],
+    fallback: [require('path').join(__dirname, 'node_modules')],
   },
   plugins: [
 TEXT

spec/dummy/client/yarn.lock

@@ -4115,7 +4115,7 @@ react-dom@^15.4.2:
     object-assign "^4.1.0"
 
 "react-on-rails@file:../../..":
-  version "6.6.0"
+  version "6.7.2"
 
 react-proxy@^1.1.7:
   version "1.1.8"

spec/react_on_rails/generators/dev_tests_generator_spec.rb

@@ -48,7 +48,7 @@
   // This fixes an issue with resolving 'react' when using a local symlinked version
   // of the node_package folder
   resolveLoader: {
-    fallback: [path.join(__dirname, 'node_modules')],
+    fallback: [require('path').join(__dirname, 'node_modules')],
   },
   plugins: [
     ...