feat!: upgrade Node.js to 14 LTS

[VerteDinde]

• I have read the contribution documentation for this project.
• I agree to follow the code of conduct that this project follows, as appropriate.
• The changes are appropriately documented (if applicable).
• The changes have sufficient test coverage (if applicable).
• The testsuite passes successfully on my local machine (if applicable).

Summarize your changes:

Relands #1393 after cutting a new version of packager with a fix for Electron 20.

[codecov]

Codecov Report

Merging #1399 (62c7006) into main (a723fa8) will decrease coverage by 0.64%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #1399      +/-   ##
==========================================
- Coverage   95.61%   94.97%   -0.65%     
==========================================
  Files          15       15              
  Lines         776      776              
==========================================
- Hits          742      737       -5     
- Misses         34       39       +5     

Impacted Files	Coverage Δ
src/mac.js	97.09% <0.00%> (-2.91%)	⬇️

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