Update building-and-testing-net.md

[kizaonline]

Removing 2.2 as it is deprecated and no longer works, adding 5.0.x as it is the latest

Why:

Remvoing 2.2 as it is deprecated and no longer works
Closes [https://github.com//issues/4954]

What's being changed:

Removing 2.2 as it is deprecated, and adding 5.0.x as the latest

Check off the following:

• I have reviewed my changes in staging. (look for the deploy-to-heroku link in your pull request, then click View deployment)
• For content changes, I have reviewed the localization checklist
• For content changes, I have reviewed the Content style guide for GitHub Docs.

[welcome]

Thanks for opening this pull request! A GitHub docs team member should be by to give feedback soon. In the meantime, please check out the contributing guidelines.

[janiceilene]

@kizaonline Thanks so much for opening a PR! I'll get this triaged for review ⚡

[martin389]

The proposed changes can be previewed here: https://docs-4953--patch-1.herokuapp.com/en/actions/guides/building-and-testing-net 🔎

[martin389]

Thanks for this PR! 🎊 Once the publishing processes have completed, the changes will be visible at https://docs.github.com/en/actions/guides/building-and-testing-net

[github-actions]

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