User Agent Header not Set

[RedlineTriad]

The following line of code is wrong: https://github.com/SonarSource/sonar-scanner-msbuild/blob/290ed63dd6d85f5fd74b564b68d11f26565d7e3e/src/SonarScanner.MSBuild.PreProcessor/WebClientDownloader.cs#L54

HttpRequestHeader.UserAgent.ToString()

returns UserAgent the name of the enum variant.

However, the correct value of the header is User-Agent as seen here: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/User-Agent

This causes reverse proxies and other logic that cares about this value (such as different auth flows for scanners than users) to break. And is very annoying to debug because it's such a small error.