fix: landing page

Author: tomalaforge

docs/src/content/docs/index.mdx

@@ -13,7 +13,7 @@ hero:
  icon: right-arrow
  variant: primary
  - text: Go to the latest Challenge
- link: /challenges/signal/53-big-signal-performance/
+ link: /challenges/signal/54-pipe-observable-to-signal/
  icon: rocket
  - text: Give a star
  link: https://github.com/tomalaforge/angular-challenges