[CI] Add testing example in the list of integration tests (#444)

Author: sebsto

.github/workflows/pull_request.yml

@@ -36,7 +36,7 @@ jobs:
       # We pass the list of examples here, but we can't pass an array as argument
       # Instead, we pass a String with a valid JSON array.
       # The workaround is mentioned here https://github.com/orgs/community/discussions/11692
-      examples: "[ 'APIGateway', 'BackgroundTasks', 'HelloJSON', 'HelloWorld', 'S3_AWSSDK', 'S3_Soto', 'Streaming' ]"
+      examples: "[ 'APIGateway', 'BackgroundTasks', 'HelloJSON', 'HelloWorld', 'S3_AWSSDK', 'S3_Soto', 'Streaming', 'Testing' ]"
 
       archive_plugin_enabled: true