Add information on secret file to readme

Change-Id: I22148257c9307cb5474d798d2f826f7f2752cc5a
diff --git a/Changes b/Changes
index ba17a44..42c17c1 100755
--- a/Changes
+++ b/Changes
@@ -1,3 +1,6 @@
+0.39 2020-06-18
+        - Add information on secret file to Readme.
+
 0.38 2020-06-16
         - Support X-Forwarded-Host name for proxy.
         - Document API URI.