Bump appengine-api-stubs from 1.9.38 to 2.0.6

Bumps [appengine-api-stubs](https://github.com/GoogleCloudPlatform/appengine-java-standard) from 1.9.38 to 2.0.6.
- [Release notes](https://github.com/GoogleCloudPlatform/appengine-java-standard/releases)
- [Commits](https://github.com/GoogleCloudPlatform/appengine-java-standard/commits/v2.0.6)

---
updated-dependencies:
- dependency-name: com.google.appengine:appengine-api-stubs
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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Author: dependabot[bot]

build.gradle

@@ -52,7 +52,7 @@ dependencies {
     testImplementation 'org.openjdk.jmh:jmh-generator-annprocess:1.35'
     testImplementation 'com.google.appengine:appengine-api-1.0-sdk:1.9.38'
     testImplementation 'com.google.appengine:appengine-api-labs:1.9.38'
-    testImplementation 'com.google.appengine:appengine-api-stubs:1.9.38'
+    testImplementation 'com.google.appengine:appengine-api-stubs:2.0.6'
     testImplementation 'com.google.appengine:appengine-testing:1.9.38'
     testImplementation 'com.squareup.okhttp:okhttp:2.7.5'
     testImplementation 'com.squareup.okhttp3:okhttp:4.0.0'