feat: Add 2023 version of site to past website lists (#107)

* Initial plan

* feat: add 2023 version to past websites

Co-authored-by: benkutil <228373+benkutil@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: benkutil <228373+benkutil@users.noreply.github.com>
Co-authored-by: Ben Kutil <thisis@benkutil.com>

Author: Copilot

src/_data/pastSites.json

@@ -6,5 +6,9 @@
   {
     "title": "2020",
     "url": "https://2020.benkutil.com"
+  },
+  {
+    "title": "2023",
+    "url": "https://2023.benkutil.com"
   }
 ]