Please provide image for NodeJS v16 LTS

Please update typo3/core-testing-js to include node:16.15-alpine instead of node:14-alpine.

I guess this needs a new docker image (like typo3/core-testing-nodejs16 name as TYPO3 v10 uses typo3/core-testing-js:latest and is unfortunately not marked to be node v16 compatible.

Or maybe we could mark TYPO3 v10 as Node v16 compatible and release v16 within typo3/core-testing-js:lastest, up to you to decide ;)

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