lint: enable intrange linter (#7331)

Enable intrange linter to enforce modern Go range syntax over
traditional for loops, by converting:

for i := 0; i < n; i++

to:

for i := range n

Adding type conversions where needed for compatibility
with existing uint64 parameters.

Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>

plugin/kubernetes/controller_test.go

@@ -70,7 +70,7 @@ func BenchmarkController(b *testing.B) {
 	m.SetQuestion("svc1.testns.svc.cluster.local.", dns.TypeA)
 
 	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for range b.N {
 		k.ServeDNS(ctx, rw, m)
 	}
 }

plugin/kubernetes/xfr.go

@@ -259,7 +259,7 @@ func emitAddressRecord(c chan<- []dns.RR, s msg.Service) string {
 func calcSRVWeight(numservices int) uint16 {
 	var services []msg.Service
 
-	for i := 0; i < numservices; i++ {
+	for range numservices {
 		services = append(services, msg.Service{})
 	}