You can see that during the build step you have a lot of warnings like this one:
CSC : warning CS8032: An instance of analyzer SonarAnalyzer.Rules.CSharp.UriShouldNotBeHardcoded cannot be created from C:\Users\jferreira\AppData\Local\Temp\.sonarqube\resources\0\SonarAnalyzer.CSharp.dll : Could not load file or assembly 'Microsoft.CodeAnalysis, Version=1.3.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.
You can also see some references to Microsoft.Net.Compilers.1.0.0 which means that you are forcing the build with an older version of Roslyn. As stated in the release notes we require at least Roslyn 1.3 so you will need to update to the version 1.3.2.
Please let me know if that didn’t solve the issue.