Update fossa check for Node deprecation

[dbussink]

This ensures we run it on Node 16, fixing the current deprecation message it shows.

Related Issue(s)

See for example the output at https://github.com/vitessio/vitess/actions/runs/4664825536

Checklist

• "Backport to:" labels have been added if this change should be back-ported
• Tests were added or are not required
• Did the new or modified tests pass consistently locally and on the CI
• Documentation was added or is not required

[vitess-bot]

Review Checklist

Hello reviewers! 👋 Please follow this checklist when reviewing this Pull Request.

General

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Bug fixes

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Non-trivial changes

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