fix: native ssh 'ssh_user_ca_key_file' config.yaml

Author: alexandreLamarre

content/docs/capabilities/native-ssh-access.mdx

@@ -131,8 +131,7 @@ Add SSH configuration to your `config.yaml`:
 
 ```yaml title="config.yaml"
 ssh_address: 0.0.0.0:22 # if port 22 is already in use by sshd, choose a different port
-ssh_user_ca_key_file:
-  - '/path/to/pomerium_user_ca_key'
+ssh_user_ca_key_file: '/path/to/pomerium_user_ca_key'
 ssh_host_key_files:
   - '/path/to/pomerium_ssh_host_ed25519_key'
   - '/path/to/pomerium_ssh_host_rsa_key'