fix: secureflag link in post

https://secureflag.com/owasp.html no longer works, replace with https://secureflag.com/owasp

_posts/2020-12-24-secureflag.md

@@ -12,8 +12,8 @@ excerpt_separator: <!--more-->
 As we close the year OWASP Foundation is proud to present a new member benefit in the form of [online training](https://secureflag.owasp.org) provided by [OWASP SecureFlag Open Platform](https://owasp.org/www-project-secureflag-open-platform/). All active OWASP members around the globe now have access to all of the great exercises and training options that the OWASP SecureFlag Open Platform supports and many more besides! 
 
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-The platform uses SSO for login using your OWASP email address so ensure that you have your OWASP email address handy (if you don't yet have one, provision one [here](https://owasp.org/manage-membership/)) and then request an activation code [here](https://www.secureflag.com/owasp.html). Once you have your activation code, [Sign Up](https://secureflag.owasp.org/signup.html) and you are ready to go!
+The platform uses SSO for login using your OWASP email address so ensure that you have your OWASP email address handy (if you don't yet have one, provision one [here](https://owasp.org/manage-membership/)) and then request an activation code [here](https://www.secureflag.com/owasp). Once you have your activation code, [Sign Up](https://secureflag.owasp.org/signup.html) and you are ready to go!
 
 For more information about the OWASP SecureFlag Open Platform check out their [project page](https://owasp.org/www-project-secureflag-open-platform/). And if you are involved with a vulnerable web application project then please reach out to the project team about getting some exercises created showcasing your project. 
 
-Not yet a member?  Then please consider [joining us](https://owasp.org/membership/).  Membership starts at $50 USD (or $20 for students) and there are discounts depending on your region.  For more details and information about what membership provides, check out the [membership page](https://owasp.org/membership/).
+Not yet a member?  Then please consider [joining us](https://owasp.org/membership/).  Membership starts at $50 USD (or $20 for students) and there are discounts depending on your region.  For more details and information about what membership provides, check out the [membership page](https://owasp.org/membership/).