docs(install): add asdf installation (#289)

Signed-off-by: Theo Bob Massard <tbobm@protonmail.com>
Co-authored-by: Xing Yahao <keidarcy.1015@gmail.com>

README.md

@@ -51,6 +51,14 @@ curl -sL https://raw.githubusercontent.com/keidarcy/e1s-install/master/cloudshel
 go install github.com/keidarcy/e1s/cmd/e1s@latest
 ```
 
+- [asdf-vm](https://asdf-vm.com/)
+
+```bash
+asdf plugin add e1s
+asdf install e1s latest
+asdf global e1s latest
+```
+
 ## Usage
 
 Make sure you have the AWS CLI installed and properly configured with the necessary permissions to access your ECS resources, and [session manager plugin](https://docs.aws.amazon.com/systems-manager/latest/userguide/session-manager-working-with-install-plugin.html) installed if you want to use the interactive exec or port forwarding features.