Fixed vault example in the README (#405)

Signed-off-by: Kai Wagner <kai.wagner@percona.com>

README.md

@@ -121,10 +121,10 @@ _See [Make Builds for Developers](https://github.com/percona/pg_tde/wiki/Make-bu
         -- For Vault-V2 key provider
         -- pg_tde_add_key_provider_vault_v2(provider_name, vault_token, vault_url, vault_mount_path, vault_ca_path)
         SELECT pg_tde_add_key_provider_vault_v2(
-            'vault-provider',
-            json_object( 'type' VALUE 'remote', 'url' VALUE 'http://localhost:8888/token' ),
-            json_object( 'type' VALUE 'remote', 'url' VALUE 'http://localhost:8888/url' ),
-            to_json('secret'::text), NULL);
+		'vault-provider',
+	        '<rootToken>',
+        	'http://vault.vault.svc.cluster.local:8200',
+	        'secret', NULL);            
 
         -- For File key provider
         -- pg_tde_add_key_provider_file(provider_name, file_path);