Add support for HSTS header

Issue: PROD-20656

Change-Id: Iffdfb32e155dc38f17e8c4f2d46641e025ea66f2
diff --git a/tests/pillar/proxy_with_ssl.sls b/tests/pillar/proxy_with_ssl.sls
index a6e498b..824fa07 100644
--- a/tests/pillar/proxy_with_ssl.sls
+++ b/tests/pillar/proxy_with_ssl.sls
@@ -224,6 +224,10 @@
             file: '/etc/ssl/client_cert.pem'
             enabled: False
           verify_client: 'off'
+          strict_transport_security:
+            max_age: 16000000
+            include_subdomains: True
+            always: True
       nginx_proxy_site02:
         enabled: true
         type: nginx_proxy