according to the official scaleway support, requests within the same session can
not be parallelized.
While I do not know for sure that this is a write-only limitation, I've
implemented it as a write-only limitation for now.
Previously requests like this would produce a 500 internal server error:
```
resource "scaleway_ip" "test_ip" {
count = 2
}
```
now this limitation should be lifted, for all scaleway resources
