refactor(template-base): replace exec/promisify with @malept/cross-spawn-promise

[malept]

• 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 have sufficient test coverage (if applicable).
• The testsuite passes successfully on my local machine (if applicable).

Summarize your changes:

Reduce the amount of uses of util.promisify because it's problematic in newer versions of TypeScript.

[codecov]

Codecov Report

Merging #2391 (fd5ecd7) into master (d5743d3) will increase coverage by 0.38%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2391      +/-   ##
==========================================
+ Coverage   74.59%   74.97%   +0.38%     
==========================================
  Files          77       91      +14     
  Lines        2299     2334      +35     
  Branches      436      436              
==========================================
+ Hits         1715     1750      +35     
  Misses        476      476              
  Partials      108      108              

Impacted Files	Coverage Δ
packages/template/base/src/determine-author.ts	100.00% <100.00%> (ø)
packages/maker/flatpak/index.ts	100.00% <0.00%> (ø)
packages/utils/async-ora/index.ts	100.00% <0.00%> (ø)
packages/maker/appx/index.ts	100.00% <0.00%> (ø)
packages/maker/dmg/index.ts	100.00% <0.00%> (ø)
packages/plugin/base/index.ts	100.00% <0.00%> (ø)
packages/template/base/index.ts	100.00% <0.00%> (ø)
packages/maker/snap/index.ts	100.00% <0.00%> (ø)
packages/maker/rpm/index.ts	100.00% <0.00%> (ø)
packages/maker/base/index.ts	100.00% <0.00%> (ø)
... and 5 more

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