Allow select ECDSA key format for the OpenSSH client known_hosts file

PROD-35539

Change-Id: Ic673396de4184bee6723df4d08688d336d0c32ce
diff --git a/README.rst b/README.rst
index 3a701d4..729f883 100644
--- a/README.rst
+++ b/README.rst
@@ -286,6 +286,17 @@
 
 See PATTERNS in ssh_config(5) for more information on what <pattern> is.
 
+* Use ECDSA key format for the OpenSSH client known_hosts file:
+
+  - If `known_hosts_use_ecdsa` is set to `true` it will use ECDSA key format
+    in known_hosts otherwise RSA key format wil be used
+
+  .. code-block:: yaml
+
+      openssh:
+        client:
+          known_hosts_use_ecdsa: true
+
 **CIS Compliance**
 
 There is a number of configuration options that make the OpenSSH service