remove outdated link

Signed-off-by: h4l0gen <[email protected]>

Author: h4l0gen

content/overview.md

@@ -7,9 +7,7 @@ A quick look at what TUF does and how it works.
 ### Purpose, or Why Get TUF?
 
 There are literally thousands of different software update systems in common
-use today. (In fact the computer of an average Windows user probably contains about [two
-dozen](https://secunia.com/gfx/pdf/Secunia_RSA_Software_Portfolio_Security_Exposure.pdf)
-different software updaters!)
+use today.
 
 What these very different systems have in common is that they all identify,
 locate, and download updates for software that can add new functionalities or