Add RepositoryType to .csproj examples

[leflings]

Why:

I was banging my head against the wall for a long time getting this kind of response when pushing (using a nuget.config file)

$ dotnet nuget push "releases/<packages>.nupkg" --source "github" --api-key <PAT_TOKEN>
Pushing <package> to 'https://nuget.pkg.github.com/<owner>'...
  PUT https://nuget.pkg.github.com/<owner>/
warn : No destination repository detected. Ensure the source project has a 'RepositoryUrl' property defined. If you're using a nuspec file, ensure that it has a repository element with the required 'type' and 'url' attributes.
  BadRequest https://nuget.pkg.github.com/<owner>/ 102ms
error: Response status code does not indicate success: 400 (Bad Request).

Adding the <RepositoryType>git</RepositoryType> solved the problem.

What's being changed:

I've added missing nodes to the .csproj examples

Check off the following:

• I have reviewed my changes in staging (look for "Automatically generated comment" and click Modified to view your latest changes).
• For content changes, I have completed the self-review checklist.

Writer impact (This section is for GitHub staff members only):

• This pull request impacts the contribution experience
  • I have added the 'writer impact' label
  • I have added a description and/or a video demo of the changes below (e.g. a "before and after video")

[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.

[github-actions]

Automatically generated comment ℹ️

This comment is automatically generated and will be overwritten every time changes are committed to this branch.

The table contains an overview of files in the content directory that have been changed in this pull request. It's provided to make it easy to review your changes on the staging site. Please note that changes to the data directory will not show up in this table.

---

Content directory changes

You may find it useful to copy this table into the pull request summary. There you can edit it to share links to important articles or changes and to give a high-level overview of how the changes in your pull request support the overall goals of the pull request.

Source	Preview	Production	What Changed
content/packages/working-with-a-github-packages-registry/working-with-the-nuget-registry.md	Modified	Original

[ramyaparimi]

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

[janiceilene]

👋 @leflings Thanks for opening a PR and thank you for your patience as we're working through a backlog of reviews 💛 I spoke with the team, and they let me know that if you try to publish a NuGet package using a .csproj file, RepositoryType is not mandatory. However, if the person is using a .nuspec to publish packages, <RepositoryType>git</RepositoryType> is necessary.

Since there aren't changes needed in this doc, I'm going to close this PR now.

Thanks so much for your interest in improving the GitHub docs ✨