chore: convert new posts

Signed-off-by: Jaime Silvela <[email protected]>

Author: jsilvela

content/blog/contributor-highlight-niccolo-fei/index.md

@@ -5,7 +5,8 @@ draft: false
 image:
     url: niccolo.jpg
     attribution:
-author: fdrees
+authors:
+ - fdrees
 tags:
  - extensions
  - kubernetes

content/releases/cloudnative-pg-1-27.0-released/index.md

@@ -2,7 +2,8 @@
 title: "CloudNativePG 1.27.0 Released!"
 date: 2025-08-12
 draft: false
-author: gbartolini
+authors:
+ - gbartolini
 image:
     url: 58364dde1adc4a0a8.37186404-2048x1445.jpg
     attribution: from <a href="https://wordpress.org/photos/photo/58364dde1a/">Saurabh</a>