[#1341] .golangci.yml: Replace exportloopref with copyloopvar

exportloopref is deprecated.
gopatch:
```
@@
var index, value identifier
var slice expression
@@
for index, value := range slice {
...
-value := value
...
}

@@
var index, value identifier
var slice expression
@@
for index, value := range slice {
...
-index := index
...
}

@@
var value identifier
var channel expression
@@
for value := range channel {
...
-value := value
...
}
```

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

pkg/services/tree/sync.go

@@ -190,8 +190,6 @@ func (s *Service) applyOperationStream(ctx context.Context, cid cid.ID, treeID s
 
 	var prev *pilorama.Move
 	for m := range operationStream {
-		m := m
-
 		// skip already applied op
 		if prev != nil && prev.Time == m.Time {
 			continue
@@ -287,8 +285,6 @@ func (s *Service) synchronizeTree(ctx context.Context, cid cid.ID, from uint64,
 	allNodesSynced.Store(true)
 
 	for i, n := range nodes {
-		i := i
-		n := n
 		errGroup.Go(func() error {
 			var nodeSynced bool
 			n.IterateNetworkEndpoints(func(addr string) bool {
@@ -421,7 +417,7 @@ func (s *Service) syncContainers(ctx context.Context, cnrs []cid.ID) {
 	var wg sync.WaitGroup
 	for _, cnr := range cnrs {
 		wg.Add(1)
-		cnr := cnr
+
 		err := s.syncPool.Submit(func() {
 			defer wg.Done()
 			s.log.Debug(logs.TreeSyncingContainerTrees, zap.Stringer("cid", cnr))