Update _index.md

Author: csscuwa

content/sign-up/_index.md

@@ -3,4 +3,4 @@ title: "Sign Up"
 type: page
 ---
 
-Please fill out the form at [http://cssc.asn.au/signup](https://server.cssc.asn.au/signup/form) to sign up to be a club member.
+Please fill out the form at [https://server.cssc.asn.au/signup/form](https://server.cssc.asn.au/signup/form) to sign up to be a club member.