Unsupported project types are included in the.. (#905)

A fix for #896.  When processing recursively through projects, apply the
supported project test and skip any projects that do no satisfy the test

Signed-off-by: Peter Cullen <peter.cullen@infor.com>

CycloneDX/Services/ProjectFileService.cs

@@ -350,6 +350,12 @@ public async Task<HashSet<DotnetDependency>> RecursivelyGetProjectReferencesAsyn
             while (files.Count > 0)
             {
                 var currentFile = files.Dequeue();
+
+                if (!Utils.IsSupportedProjectType(currentFile))
+                {
+                    continue;
+                }
+
                 // Find all project references inside of currentFile
                 var foundProjectReferences = await GetProjectReferencesAsync(currentFile).ConfigureAwait(false);