chore(ubergen): Revert "chore: remove 'ubergen exclude' from example …

…package (aws#19177)" (aws#19540)

This reverts commit c94c277.

In the `v2-main` branch all packages are private, which causes ubergen to exclude all of them, which we don't want.

----

### All Submissions:

* [ ] Have you followed the guidelines in our [Contributing guide?](https://github.com/aws/aws-cdk/blob/master/CONTRIBUTING.md)

### Adding new Unconventional Dependencies:

* [ ] This PR adds new unconventional dependencies following the process described [here](https://github.com/aws/aws-cdk/blob/master/CONTRIBUTING.md/#adding-new-unconventional-dependencies)

### New Features

* [ ] Have you added the new feature to an [integration test](https://github.com/aws/aws-cdk/blob/master/INTEGRATION_TESTS.md)?
	* [ ] Did you use `cdk-integ` to deploy the infrastructure and generate the snapshot (i.e. `cdk-integ` without `--dry-run`)?

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/example-construct-library/package.json

@@ -111,5 +111,8 @@
     "env": {
       "AWSLINT_BASE_CONSTRUCT": true
     }
+  },
+  "ubergen": {
+    "exclude": true
   }
 }

packages/cdk-cli-wrapper/package.json

@@ -98,5 +98,8 @@
   "maturity": "experimental",
   "publishConfig": {
     "tag": "latest"
+  },
+  "ubergen": {
+    "exclude": true
   }
 }

tools/@aws-cdk/pkglint/lib/rules.ts

@@ -1733,6 +1733,18 @@ export class UbergenPackageVisibility extends ValidationRule {
           },
         });
       }
+    } else {
+      if (pkg.json.private && !pkg.json.ubergen?.exclude) {
+        pkg.report({
+          ruleName: this.name,
+          message: 'ubergen.exclude must be configured for private packages',
+          fix: () => {
+            pkg.json.ubergen = {
+              exclude: true,
+            };
+          },
+        });
+      }
     }
   }
 }

tools/@aws-cdk/ubergen/bin/ubergen.ts

@@ -129,7 +129,7 @@ async function findLibrariesToPackage(uberPackageJson: PackageJson): Promise<rea
   for (const dir of await fs.readdir(librariesRoot)) {
     const packageJson = await fs.readJson(path.resolve(librariesRoot, dir, 'package.json'));
 
-    if (packageJson.private || packageJson.ubergen?.exclude) {
+    if (packageJson.ubergen?.exclude) {
       console.log(`\t⚠️ Skipping (ubergen excluded):   ${packageJson.name}`);
       continue;
     } else if (packageJson.jsii == null ) {