fix(doc): add scoop-extras installation details

[cheapestorderconcept]

Adding the solution to errors couldn't find manifest for 'skaffold' when installing with scoop. This error is due to lack of extras bucket when scoop is being installed. Default bucket that comes with scoop is main. In the absence of the extras bucket, users won't be able to install skaffold and couldn't find manifest for 'skaffold' error will be encountered

Fixes: #nnn
Related: Relevant tracking issues, for context
Merge before/after: Dependent or prerequisite PRs

Description

User facing changes (remove if N/A)

Follow-up Work (remove if N/A)

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[cheapestorderconcept]

@googlebot I signed it!

[briandealwis]

Since the extras bucket isn't configured by default, it might be better to integrate the add extras directly into the main part of the text. Something like:

Skaffold can be installed using the [Scoop package manager](https://scoop.sh/) from the [extras bucket](https://github.com/lukesampson/scoop-extras#readme). This package is not maintained by the Skaffold team.
```powershell
scoop bucket add extras
scoop install skaffold

[MarlonGamez]

hey @cheapestorderconcept, are you still interested in getting this merged? I think the point that @briandealwis made makes sense, I think it would be good to incorporate it

[briandealwis]

Closing in favour of #6847.