remove EOL distro versions

aws/README-zh.md

@@ -8,8 +8,7 @@
 
 - Amazon EC2 实例类型
 > **注：** 在某些 AWS 区域中，此模版提供的某些实例类型可能不可用。比如 `m5a.large` 可能无法在 `ap-east-1` 区域部署（仅为假设）。在此情况下，你会在部署过程中遇到此错误：`The requested configuration is currently not supported. Please check the documentation for supported configurations`。新开放的 AWS 区域更容易出现此问题，因为它们提供的实例类型较少。如需了解更多关于实例可用性的信息，请参见 [https://ec2instances.info](https://ec2instances.info)。
-- VPN 服务器的操作系统（Ubuntu 20.04/18.04/16.04, Debian 9, CentOS 8/7, Amazon Linux 2）
-> **注：** 在 EC2 上使用 Debian 9 映像之前，你需要先在 AWS Marketplace 上订阅：[Debian 9](https://aws.amazon.com/marketplace/pp/B073HW9SP3)。
+- VPN 服务器的操作系统（Ubuntu 20.04, CentOS 7, Amazon Linux 2）
 - 你的 VPN 用户名
 - 你的 VPN 密码
 - 你的 VPN IPsec PSK（预共享密钥）

aws/README.md

@@ -8,8 +8,7 @@ Available customization parameters:
 
 - Amazon EC2 instance type
 > **Note**: It is possible that not all instance type options offered by this template are available in a specific AWS region. For example, you may not be able to deploy an `m5a.large` instance in `ap-east-1` (hypothetically). In that case, you might experience the following error during deployment: `The requested configuration is currently not supported. Please check the documentation for supported configurations`. Newly released regions are more prone to having this problem as there are less variety of instances. For more info about instance type availability, refer to [https://ec2instances.info](https://ec2instances.info).
-- OS for your VPN server (Ubuntu 20.04/18.04/16.04, Debian 9, CentOS 8/7, Amazon Linux 2)
-> **Note:** Before using the Debian 9 image on EC2, you need to first subscribe at the AWS Marketplace: [Debian 9](https://aws.amazon.com/marketplace/pp/B073HW9SP3).
+- OS for your VPN server (Ubuntu 20.04, CentOS 7, Amazon Linux 2)
 - Your VPN username
 - Your VPN password
 - Your VPN IPsec PSK (pre-shared key)