chore: retain the major version 4 for codegen (#591)

* Revert "fix: codegen downgrade to version 3 (#589)"

This reverts commit c1f9f36.

* fix: use hard code codegen version in schema.js

* fix lint

Author: AaronZyLee

packages/amplify-codegen/package.json

@@ -1,6 +1,6 @@
 {
   "name": "amplify-codegen",
-  "version": "3.4.4",
+  "version": "4.0.0",
   "description": "amplify code generator",
   "repository": {
     "type": "git",

packages/amplify-codegen/src/commands/statements.js

@@ -63,6 +63,9 @@ async function generateStatements(context, forceDownloadSchema, maxDepth, withou
       const generatedOps = generateGraphQLDocuments(schemaData, {
         maxDepth: maxDepth || cfg.amplifyExtension.maxDepth,
         useExternalFragmentForS3Object: (language === 'graphql'),
+        // default typenameIntrospection to true when not set
+        typenameIntrospection:
+          cfg.amplifyExtension.typenameIntrospection === undefined ? true : !!cfg.amplifyExtension.typenameIntrospection,
       });
       if(!generatedOps) {
         context.print.warning('No GraphQL statements are generated. Check if the introspection schema has GraphQL operations defined.');

packages/amplify-codegen/tests/commands/statements.test.js

@@ -97,7 +97,7 @@ describe('command - statements', () => {
       path.join(MOCK_PROJECT_ROOT, MOCK_SCHEMA),
       MOCK_APIS[0],
       MOCK_REGION,
-      forceDownload
+      forceDownload,
     );
   });
 
@@ -110,7 +110,7 @@ describe('command - statements', () => {
       path.join(MOCK_PROJECT_ROOT, MOCK_SCHEMA),
       MOCK_APIS[0],
       MOCK_REGION,
-      forceDownload
+      forceDownload,
     );
   });