chore: Don't test with node 10 or 15

[nickserv]

What: Don't test with node 10 or 15

Why: Node 10 and 15 reached EOL so let's free up some CI resources.

How: Remove 10 and 15 from node test matrix.

Checklist:

• [ ] Documentation added to the
  docs site
• Tests
• [ ] Typescript definitions updated
• Ready to be merged
  

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[codecov]

Codecov Report

Merging #975 (239d848) into main (56a4c75) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##              main      #975   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           26        26           
  Lines          966       966           
  Branches       298       298           
=========================================
  Hits           966       966           

Flag	Coverage Δ
node-10.14.2	?
node-12	100.00% <ø> (ø)
node-14	100.00% <ø> (ø)
node-15	?
node-16	100.00% <ø> (ø)

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[MatanBobi]

I'm not 100% familiar with the approach but should we bump a major version stating that from now on we don't support Node 10 and 15?

[eps1lon]

I'm not 100% familiar with the approach but should we bump a major version stating that from now on we don't support Node 10 and 15?

Let's just drop node 10 support in this PR as well i.e. close #957 and target the alpha branch

[eps1lon]

Closed in #976