refactor: remove unneeded in Go 1.22 loop var copy (#4856)

The PR cleans up unnecessary loop variable copying and enables the
[`copyloopvar`](https://golangci-lint.run/usage/linters/#copyloopvar)
linter for detecting this redundant variable copying.

#### Additional notes

After the project upgraded to Go version 1.22 in #4779, copying
variables inside a `for` loop became unnecessary. See this [blog
post](https://go.dev/blog/loopvar-preview) for a detailed explanation.

The `copyloopvar` linter is only available from `golangci-lint` v1.57
onwards, so we also need to update this tool.

internal/pipe/blob/upload.go

@@ -137,7 +137,6 @@ func doUpload(ctx *context.Context, conf config.Blob) error {
 
 	g := semerrgroup.New(ctx.Parallelism)
 	for _, artifact := range ctx.Artifacts.Filter(filter).List() {
-		artifact := artifact
 		g.Go(func() error {
 			// TODO: replace this with ?prefix=folder on the bucket url
 			dataFile := artifact.Path
@@ -152,8 +151,6 @@ func doUpload(ctx *context.Context, conf config.Blob) error {
 		return err
 	}
 	for name, fullpath := range files {
-		name := name
-		fullpath := fullpath
 		g.Go(func() error {
 			uploadFile := path.Join(dir, name)
 			return uploadData(ctx, conf, up, fullpath, uploadFile, bucketURL)