Typos in v2 setup for GCS

[choonchernlim]

I noticed there are typos in the gcs block in the v2 module:.

dynamic "gcs" {
  for_each = volumes.value.gcs[*]
  content {
    bucket    = gcs.value["medium"]     # should be "bucket" instead of "medium"
    read_only = gcs.value["size_limit"] # should be "read_only" instead of "size_limit"
  }
}

I reckon it's due to accidental copy/paste from the block above it. Thanks.