Add hook for unchanged certificates.

hook.sh.example

@@ -52,4 +52,24 @@ function deploy_cert {
     #   The path of the file containing the intermediate certificate(s).
 }
 
+function unchanged_cert {
+    local DOMAIN="${1}" KEYFILE="${2}" CERTFILE="${3}" FULLCHAINFILE="${4}" CHAINFILE="${5}"
+
+    # This hook is called once for each certificate that is still
+    # valid and therefore wasn't reissued.
+    #
+    # Parameters:
+    # - DOMAIN
+    #   The primary domain name, i.e. the certificate common
+    #   name (CN).
+    # - KEYFILE
+    #   The path of the file containing the private key.
+    # - CERTFILE
+    #   The path of the file containing the signed certificate.
+    # - FULLCHAINFILE
+    #   The path of the file containing the full certificate chain.
+    # - CHAINFILE
+    #   The path of the file containing the intermediate certificate(s).
+}
+
 HANDLER=$1; shift; $HANDLER $@