[#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/local_object_storage/engine/shards.go

@@ -367,7 +367,6 @@ func (e *StorageEngine) closeShards(deletedShards []hashedShard) error {
 	var multiErrGuard sync.Mutex
 	var eg errgroup.Group
 	for _, sh := range deletedShards {
-		sh := sh
 		eg.Go(func() error {
 			err := sh.SetMode(mode.Disabled)
 			if err != nil {