website: Fix the gem5-tutorial-codespace link

This patch changes this into a link instead of plain-text.

Change-Id: I4641dd4626920c6867116c71e21a9fe6e6fb9bc5
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5-website/+/68577
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: Bobby Bruce <bbruce@ucdavis.edu>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
diff --git a/_pages/events/hpca-2023.md b/_pages/events/hpca-2023.md
index 55b94e1..aa6f252 100644
--- a/_pages/events/hpca-2023.md
+++ b/_pages/events/hpca-2023.md
@@ -9,7 +9,7 @@
 
 Slides: [PDF](/assets/files/isca2022-tutorial/gem5-tutorial-hpca-2023.pdf), [Powerpoint](/assets/files/isca2022-tutorial/gem5-tutorial-hpca-2023.pptx).
 
-GitHub Repository Used: https://github.com/gem5-hpca-2023/gem5-tutorial-codespace
+GitHub Repository Used: <https://github.com/gem5-hpca-2023/gem5-tutorial-codespace>
 
 
 ## Event page