為IPv6-only VPS 添加IPv4連接 (Ubuntu 20.04)

參考：Changing the DNS servers Ubuntu Server 20.04 - Arm64 (Raspi) - Ask Ubuntu

1. cd /etc/netplan
2. nano 50-cloud-init.yaml

3. ethernets:
       [network-device]:
           ...
           nameservers:
               addresses: ['2a01:4f9:c010:3f02::1','2a00:1098:2c::1','2a00:1098:2b::1']
   

4. netplan apply
5. systemd-resolve --status

2a01:4f9:c010:3f02::1,2a00:1098:2c::1,2a00:1098:2b::1為NAT64的Nameservers