cmd/dex: adapt to prometheus API change

Signed-off-by: Stephan Renatus <srenatus@chef.io>

cmd/dex/serve.go

@@ -83,7 +83,7 @@ func serve(cmd *cobra.Command, args []string) error {
 		return fmt.Errorf("failed to register Go runtime metrics: %v", err)
 	}
 
-	err = prometheusRegistry.Register(prometheus.NewProcessCollector(os.Getpid(), ""))
+	err = prometheusRegistry.Register(prometheus.NewProcessCollector(prometheus.ProcessCollectorOpts{}))
 	if err != nil {
 		return fmt.Errorf("failed to register process metrics: %v", err)
 	}