docs: Upgrade hugo and docsy versions to enable collapsible nav

[maggieneterval]

Fixes: #8389

Description

Docsy now supports collapsing/expanding menu options (https://www.docsy.dev/docs/adding-content/navigation/#section-menu-options), which improves the navigability of skaffold.dev documentation. (See https://kubernetes.io/docs/home/ nav as an example.)

Before breaking up the Builders page into sub-pages (#8382), I wanted to ensure that sections were collapsible because the Build nav menu already has many sub-pages. 😄

This PR:

1. Updates the hugo and docsy versions. (Note that these are not the latest releases, as updating to the latest versions introduced some errors to the build that it would be easier to address separately before upgrading.)
2. Adds sidebar_menu_foldable = true to config.toml.

User facing changes

Before:

After:

[aaron-prindle]

Awesome, great idea to add this! Just tried it locally works great. LGTM!

[codecov]

Codecov Report

Merging #8398 (2ceb653) into main (290280e) will decrease coverage by 4.60%.
The diff coverage is 54.85%.

@@            Coverage Diff             @@
##             main    #8398      +/-   ##
==========================================
- Coverage   70.48%   65.88%   -4.60%     
==========================================
  Files         515      605      +90     
  Lines       23150    29819    +6669     
==========================================
+ Hits        16317    19646    +3329     
- Misses       5776     8700    +2924     
- Partials     1057     1473     +416     

Impacted Files	Coverage Δ
cmd/skaffold/app/cmd/completion.go	13.04% <0.00%> (-1.25%)	⬇️
cmd/skaffold/app/cmd/config/list.go	65.21% <ø> (ø)
cmd/skaffold/app/cmd/config/set.go	88.72% <ø> (ø)
cmd/skaffold/app/cmd/config/util.go	54.28% <ø> (ø)
cmd/skaffold/app/cmd/credits.go	100.00% <ø> (ø)
cmd/skaffold/app/cmd/credits/export.go	0.00% <0.00%> (ø)
cmd/skaffold/app/cmd/deploy.go	40.90% <0.00%> (-12.94%)	⬇️
cmd/skaffold/app/cmd/generate_pipeline.go	60.00% <ø> (ø)
cmd/skaffold/app/cmd/inspect_modules.go	65.00% <ø> (ø)
cmd/skaffold/app/cmd/inspect_profiles.go	66.66% <ø> (ø)
... and 416 more

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