Introduce HSTS header for https_only conf

Change-Id: If2aafcda5478cdfc91a65220542e420ca6893e07
diff --git a/Changes b/Changes
index 271cf05..e991976 100755
--- a/Changes
+++ b/Changes
@@ -9,6 +9,7 @@
         - Establish CSP plugin.
         - Added nonce helper to CSP plugin.
         - Remove no-js class in nonced inline script.
+        - Introduce HSTS header for https_only conf.
 
 0.40 2020-12-17
         - Modernize ES and fix in-loops.