chore: add auto-merge for deps update

Author: Alexander Melnyk

.gitattributes

@@ -13,11 +13,22 @@ const project = new awscdk.AwsCdkConstructLibrary({
   devDeps: [
     '@types/prettier@2.6.0', // pin until breaking changes is resolved: https://github.com/DefinitelyTyped/DefinitelyTyped/discussions/60310
   ],
+  depsUpgradeOptions: {
+    ignoreProjen: false,
+    workflowOptions: {
+      labels: ['auto-approve', 'auto-merge'],
+      secret: 'AUTOMATION_TOKEN',
+    },
+  },
   github: false,
   publishToPypi: {
     distName: 'cdk-lambda-powertools-python-layer',
     module: 'cdk_lambda_powertools_python_layer',
   },
+  autoApproveOptions: {
+    secret: 'PROJEN_GITHUB_TOKEN',
+    allowedUsernames: ['am29d'],
+  },
   license: 'MIT-0',
   copyrightOwner: 'Amazon.com, Inc. or its affiliates. All Rights Reserved.',
 });