refactors sarif test

[dani-santos-code]

reference: https://github.com/Shopify/kubeaudit/pull/453/files#r938176410

this PR:

• exports the results field in the Report struct:

type Report struct {
	Results []Result
}

• renames results function to GetResults:

func (r *Report) GetResults() []Result

[genevieveluyt]

I added some commits to:

1. Add a NewReport function so we don't have to make any breaking changes
2. Make workloadResult exported so you can use it in your test

Lmk what you think. The tests themselves look great!

[dani-santos-code]

great idea! renaming Results to GetResults was an unnecessary breaking change when we can just export workloadResult. Also liked the wrapper around Results, with NewReport. Thanks for pairing on this! 🙏