deps: bump node from 12 to 14

[peaceiris]

Related to https://github.com/actions/runner/issues/772

https://github.com/peaceiris/actions-gh-pages/pull/539/checks?check_run_id=1437553870#step:19:20 Error: System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values. (Parameter ''using: node14' is not supported, use 'docker' or 'node12' instead.')

[codecov[bot]]

Codecov Report

Merging #539 (7f110b8) into main (8cc3a89) will decrease coverage by 0.36%. The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #539      +/-   ##
==========================================
- Coverage   61.17%   60.80%   -0.37%     
==========================================
  Files           4        4              
  Lines         273      273              
  Branches       48       48              
==========================================
- Hits          167      166       -1     
- Misses        105      106       +1     
  Partials        1        1              

Impacted Files	Coverage Δ
src/utils.ts	97.61% <0.00%> (-2.39%)	:arrow_down:

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[CCKNBC]

Please Upgrade to node16 https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12