chore: update node engine requirement >= 16

[erisu]

Platforms affected

n/a

Motivation and Context

• prepare for next major node requirement
• node 14 support EOL coming in April

Description

Set node engine requirement to >=16

Testing

n/a

Checklist

• I've run the tests to see all new and existing tests pass
• I added automated test coverage as appropriate for this change
• Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• I've updated the documentation if necessary

[codecov-commenter]

Codecov Report

Merging #909 (8e652c6) into master (6aa4c09) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #909   +/-   ##
=======================================
  Coverage   88.27%   88.27%           
=======================================
  Files          46       46           
  Lines        2123     2123           
=======================================
  Hits         1874     1874           
  Misses        249      249           

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