Fix remaining wsl_v5 whitespace findings (refs #61)

Insert the blank line wsl_v5 requires above `defer` and `go`
statements that share no variables with the statement above them.
Applied mechanically via `make lint-fix`; the diff is 60 added blank
lines and nothing else.

internal/storage/s3.go

@@ -68,6 +68,7 @@ func (s *S3Storer) List(ctx context.Context, prefix string) ([]string, error) {
 // ListStream returns a channel of ObjectInfo for large result sets.
 func (s *S3Storer) ListStream(ctx context.Context, prefix string) <-chan ObjectInfo {
 	ch := make(chan ObjectInfo)
+
 	go func() {
 		defer close(ch)