fix(docs): broken link to preview

Signed-off-by: Gabriele Bartolini <[email protected]>

Author: gbartolini

content/docs/preview.md

@@ -1,6 +1,6 @@
 ---
 release:  1.28.0-rc1
-location: /documentation/1.28
+location: /documentation/preview
 release_date: 07 Nov 2025
 release_notes: https://github.com/cloudnative-pg/cloudnative-pg/releases/tag/v1.28.0-rc1
 ---