correct readme example

Author: stve

README.md

@@ -32,9 +32,11 @@ All `nil` values will fallback to their default values. `SecureHeaders::OPT_OUT`
 ```ruby
 SecureHeaders::Configuration.default do |config|
   config.cookies = {
-    secure: true, # mark all cookies as "secure"
-    httponly: true, # mark all cookies as "httponly"
-    samesite: true
+    secure: true, # mark all cookies as "Secure"
+    httponly: true, # mark all cookies as "HttpOnly"
+    samesite: {
+      strict: true # mark all cookies as SameSite=Strict
+    }
   }
   config.hsts = "max-age=#{20.years.to_i}; includeSubdomains; preload"
   config.x_frame_options = "DENY"