chore: auto approve mergify backports (backport #177) (#179)

This is an automatic backport of pull request #177 done by [Mergify](https://mergify.com).


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Author: mergify[bot]

.github/workflows/auto-approve.yml

@@ -14,7 +14,7 @@ const project = new awscdk.AwsCdkConstructLibrary({
   repositoryUrl: 'https://github.com/cdklabs/awscdk-asset-kubectl.git',
   homepage: 'https://github.com/cdklabs/awscdk-asset-kubectl#readme',
   autoApproveOptions: {
-    allowedUsernames: ['aws-cdk-automation'],
+    allowedUsernames: ['aws-cdk-automation', 'mergify[bot]'],
     secret: 'GITHUB_TOKEN',
   },
   autoApproveUpgrades: true,