feat(executor)!: Change argoexec base image to alpine. Closes #5720

[alexec]

Closes #5720

[codecov]

Codecov Report

Merging #6006 (e3f9571) into master (3cfc96b) will decrease coverage by 0.04%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #6006      +/-   ##
==========================================
- Coverage   47.35%   47.30%   -0.05%     
==========================================
  Files         248      248              
  Lines       15663    15663              
==========================================
- Hits         7417     7410       -7     
- Misses       7316     7321       +5     
- Partials      930      932       +2     

Impacted Files	Coverage Δ
workflow/metrics/server.go	12.50% <0.00%> (-4.17%)	⬇️
cmd/argo/commands/get.go	56.45% <0.00%> (-0.65%)	⬇️
workflow/controller/operator.go	70.39% <0.00%> (-0.28%)	⬇️
cmd/argoexec/commands/emissary.go	50.00% <0.00%> (+1.56%)	⬆️

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[terrytangyuan]

LGTM

[alexec]

Do not merge this PR. Let's hold it back for v3.2