Use Directory.CreateTempSubdirectory (#607)

* Use Directory.CreateTempSubdirectory

The advantage here is that the folder gets the correct permissions on Unix.

src/Aspire.Hosting/DistributedApplicationBuilder.cs

@@ -40,7 +40,7 @@ public DistributedApplicationBuilder(DistributedApplicationOptions options)
         _innerBuilder.Services.AddHostedService<DcpHostService>();
 
         // We need a unique path per application instance
-        var path = Path.Combine(Path.GetTempPath(), Path.GetRandomFileName());
+        var path = Directory.CreateTempSubdirectory().FullName;
         _innerBuilder.Services.AddSingleton(new Locations(path));
         _innerBuilder.Services.AddSingleton<KubernetesService>();