refactor: run Go modernize (#5002)

utils/singleton/singleton.go

@@ -9,7 +9,7 @@ import (
 )
 
 var (
-	instances = map[string]interface{}{}
+	instances = map[string]any{}
 	pending   = map[string]chan struct{}{}
 	lock      sync.RWMutex
 )

utils/singleton/singleton_test.go

@@ -69,7 +69,7 @@ var _ = Describe("GetInstance", func() {
 		done.Add(numCallsToDo)
 
 		numInstancesCreated = 0
-		for i := 0; i < numCallsToDo; i++ {
+		for range numCallsToDo {
 			go func() {
 				// This is needed to make sure the test does not hang if it fails
 				defer GinkgoRecover()