fix config example error

[sshw] 2020/07/22 10:06:19 [error] load config error yaml: line 2: mapping values are not allowed in this context

```
- name: server with jump
   user: appuser
   host: 192.168.8.35
   port: 22
   password: 123456
   jump:
   - user: appuser
     host: 192.168.8.36
     port: 2222
```

fix:

```
- name: server with jump
  user: appuser
  host: 192.168.8.35
  port: 22
  password: 123456
  jump:
  - user: appuser
    host: 192.168.8.36
    port: 2222
```

README.md

@@ -32,14 +32,14 @@ config example:
 - { name: ⚡️ server with emoji name, host: 192.168.8.35 }
 - { name: server with alias, alias: dev, host: 192.168.8.35 }
 - name: server with jump
-   user: appuser
-   host: 192.168.8.35
-   port: 22
-   password: 123456
-   jump:
-   - user: appuser
-     host: 192.168.8.36
-     port: 2222
+  user: appuser
+  host: 192.168.8.35
+  port: 22
+  password: 123456
+  jump:
+  - user: appuser
+    host: 192.168.8.36
+    port: 2222
 
 
 # server group 1