cli/tabwriter: Remove usage of runewidth with utf8

[vvoland]

Something I noticed a while ago when implementing the docker images --tree but forgot about posting:

Align with upstream implementation: https://github.com/golang/go/blob/6da16013ba4444e0d71540f68279f0283a92d05d/src/text/tabwriter/tabwriter.go#L417

This allows us to drop the dependency on mattn/go-runewidth package.

Also, runewidth doesn't actually provide correct results in some cases.
For comparison:

utf8.RuneCountInString("👍") = 1
runewidth.StringWidth("👍") = 2

In this case, the "thumbs up" emoji takes one cell, so its width should be equal to 1.
Actually, the correct value is 2 as it actually takes two cells!

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 44.44%. Comparing base (25bdd5c) to head (82f7307).

❗ There is a different number of reports uploaded between BASE (25bdd5c) and HEAD (82f7307). Click for more details.

HEAD has 5 uploads less than BASE

Flag	BASE (25bdd5c)	HEAD (82f7307)
	21	16

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #5749       +/-   ##
===========================================
- Coverage   59.51%   44.44%   -15.08%     
===========================================
  Files         346        6      -340     
  Lines       29376      261    -29115     
===========================================
- Hits        17483      116    -17367     
+ Misses      10923      139    -10784     
+ Partials      970        6      -964     

[thaJeztah]

Ah! Looks liike this doesn't work though 🤔

Wondering if rune count != width. The problem this package was solving is for both wide characters, but I think also characters that are multiple runes, but take up 1 column.

[vvoland]

Right! So in this case, is the upstream Go implementation wrong now? https://github.com/golang/go/blob/6da16013ba4444e0d71540f68279f0283a92d05d/src/text/tabwriter/tabwriter.go#L417 😅

[vvoland]

Hmm right, so looks like we explicitly forked tabwriter to change that: #3568

Let me close this PR then 😅

TIL

[thaJeztah]

Ah, yes, had to read back the other issues, but I think the go implementation has bugs, but they closed it as WONTFIX; golang/go#8273 (comment)