add HelloJSON example + README #304

Job	Run time
musl	1m 37s
Integration Tests / Test archive plugin	2m 21s
Soundness / API breakage check	1m 46s
Soundness / Documentation check	1m 30s
Integration Tests / Test Examples/APIGateway on 6.0.1-amazonlinux2	1m 23s
Integration Tests / Test Examples/BackgroundTasks on 6.0.1-amazonlinux2	1m 29s
Soundness / Unacceptable language check	3s
Integration Tests / Test Examples/HelloJSON on 6.0.1-amazonlinux2	1m 20s
Soundness / Broken symlinks check	7s
Soundness / Format check	38s
Integration Tests / Test Examples/HelloWorld on 6.0.1-amazonlinux2	1m 26s
Integration Tests / Test Examples/S3_AWSSDK on 6.0.1-amazonlinux2	3m 59s
Soundness / License headers check	4s
Soundness / Shell check	0s
Integration Tests / Test Examples/S3_Soto on 6.0.1-amazonlinux2	4m 27s
Soundness / YAML lint check	5s
Integration Tests / Test Examples/Streaming on 6.0.1-amazonlinux2	1m 19s
Swift 6 Language Mode / Swift 6 language mode	1m 15s
Soundness / Python lint check	0s
Unit tests / Unit tests / Windows (6.0)	3s
Unit tests / Unit tests / Windows (nightly-6.0)	2s
Unit tests / Unit tests / Windows (nightly-main)	3s
Unit tests / Unit tests / Linux (5.9)	30s
Unit tests / Unit tests / Linux (5.10)	26s
Unit tests / Unit tests / Linux (6.0)	1m 25s
Unit tests / Unit tests / Linux (nightly-6.0)	1m 46s
Unit tests / Unit tests / Linux (nightly-main)	1m 42s
	30m 46s

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