fix(cli): re-add shebang to electron-forge binary

[malept]

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• I agree to follow the code of conduct that this project follows, as appropriate.

Summarize your changes:

Fixes #2670 and the eslint(-plugin-node) rule that caused it.

See also: https://github.com/mysticatea/eslint-plugin-node/blob/v11.1.0/docs/rules/shebang.md

[codecov]

Codecov Report

Merging #2671 (c890075) into master (c5490b6) will decrease coverage by 1.64%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2671      +/-   ##
==========================================
- Coverage   65.76%   64.12%   -1.65%     
==========================================
  Files          77       77              
  Lines        2737     2606     -131     
  Branches      679      583      -96     
==========================================
- Hits         1800     1671     -129     
+ Misses        804      752      -52     
- Partials      133      183      +50     

Impacted Files	Coverage Δ
packages/api/cli/src/electron-forge.ts	58.06% <ø> (ø)
packages/api/core/src/api/start.ts	48.88% <0.00%> (-25.58%)	⬇️
packages/plugin/base/src/Plugin.ts	62.50% <0.00%> (-25.00%)	⬇️
packages/installer/exe/src/InstallerExe.ts	50.00% <0.00%> (-25.00%)	⬇️
packages/api/core/src/api/publish.ts	45.26% <0.00%> (-23.67%)	⬇️
packages/api/core/src/api/install.ts	57.60% <0.00%> (-11.33%)	⬇️
packages/installer/dmg/src/util/hdiutil.ts	42.30% <0.00%> (-9.55%)	⬇️
packages/api/core/src/api/index.ts	48.83% <0.00%> (-8.95%)	⬇️
packages/installer/base/src/Installer.ts	50.00% <0.00%> (-7.15%)	⬇️
packages/api/core/src/util/yarn-or-npm.ts	88.23% <0.00%> (-6.21%)	⬇️
... and 26 more

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