zlib.csproj shows an error when working with nuget-inspector

Hi,
I am getting the following error when trying to use zlib.csproj with nuget inspector.

**nuget-inspector --project-file zlib.csproj --json out.json**

Scan completed with Errors or Warnings: JSON file created at: out.json

ERROR: Failed to process project file: zlib.csproj with:
Microsoft.Build.Exceptions.InvalidProjectFileException: The project file "/home/zlib.csproj" must be opened in the Visual Studio IDE and converted to the latest version before it can be built by MSBuild. /home/zlib.csproj
at Microsoft.Build.Shared.ProjectErrorUtilities.ThrowInvalidProject(String errorSubCategoryResourceName, IElementLocation elementLocation, String resourceName, Object[] args)
at Microsoft.Build.Shared.ProjectErrorUtilities.VerifyThrowInvalidProject[T1](Boolean condition, String errorSubCategoryResourceName, IElementLocation elementLocation, String resourceName, T1 arg0)
at Microsoft.Build.Construction.ProjectParser.Parse()
at Microsoft.Build.Construction.ProjectParser.Parse(XmlDocumentWithLocation document, ProjectRootElement projectRootElement)
at Microsoft.Build.Construction.ProjectRootElement..ctor(String path, ProjectRootElementCacheBase projectRootElementCache, Boolean preserveFormatting)
at Microsoft.Build.Construction.ProjectRootElement.CreateProjectFromPath(String projectFile, ProjectRootElementCacheBase projectRootElementCache, Boolean preserveFormatting)
at Microsoft.Build.Construction.ProjectRootElement.<>c.b__208_0(String path, ProjectRootElementCacheBase cache)
at Microsoft.Build.Evaluation.ProjectRootElementCache.Get(String projectFile, OpenProjectRootElement loadProjectRootElement, Boolean isExplicitlyLoaded, Nullable1 preserveFormatting) at Microsoft.Build.Construction.ProjectRootElement.OpenProjectOrSolution(String fullPath, IDictionary2 globalProperties, String toolsVersion, ProjectRootElementCacheBase projectRootElementCache, Boolean isExplicitlyLoaded)
at Microsoft.Build.Evaluation.Project.ProjectImpl..ctor(Project owner, String projectFile, IDictionary2 globalProperties, String toolsVersion, String subToolsetVersion, ProjectLoadSettings loadSettings, EvaluationContext evaluationContext) at Microsoft.Build.Evaluation.Project..ctor(String projectFile, IDictionary2 globalProperties, String toolsVersion, String subToolsetVersion, ProjectCollection projectCollection, ProjectLoadSettings loadSettings, EvaluationContext evaluationContext, IDirectoryCacheFactory directoryCacheFactory)
at Microsoft.Build.Evaluation.Project..ctor(String projectFile, IDictionary`2 globalProperties, String toolsVersion)
at NugetInspector.ProjectFileProcessor.GetPackageReferences() in ./nuget-inspector/ProjectFileProcessor.cs:line 134
at NugetInspector.ProjectFileProcessor.ResolveUsingLib() in ./nuget-inspector/ProjectFileProcessor.cs:line 427
at NugetInspector.ProjectScanner.RunScan() in ./nuget-inspector/ProjectScanner.cs:line 293

ERRORS at the dependencies level: