Add support nifcloud_volume 4000 size

[fuku2014]

Description

• Resolved terraformからの高速フラッシュストレージの新規作成時の最大ディスク容量について #144

How Has This Been Tested?

• Buld with make install command.

make install

• Apply this example.

terraform {
  required_providers {
    nifcloud = {
      source = "nifcloud/nifcloud"
    }
  }
}

provider "nifcloud" {
  region = "jp-east-1"
}

resource "nifcloud_volume" "basic" {
  size = 4000
  volume_id = "example"
  disk_type = "High-Speed Storage B"
  instance_id = "your instance id"
}

• Run acceptance tests.

TF_ACC=1 go test ./nifcloud/acc/... -v -count 1 -parallel 1 -timeout 360m -run TestAcc_Volume

• Enjoy!!😸

Types of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Refactoring (improves code quality but has no user-facing effect)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation

[o108minmin]

LGTM