docs: blog post for testing PostgreSQL 19 Beta 1 (#446)

Add a blog post explaining how to test PostgreSQL 19 Beta 1 in a
Kubernetes cluster with CloudNativePG, using the newly published
19beta1-minimal-trixie operand image from postgres-containers.

Signed-off-by: Gabriele Bartolini <gabriele.bartolini@enterprisedb.com>

Author: gbartolini

content/blog/postgresql-19-beta1/elephant-ship.png

@@ -0,0 +1,62 @@
+---
+title: "How to test PostgreSQL 19 beta in your Kubernetes cluster"
+date: 2026-06-05
+draft: false
+image:
+    url: elephant-ship.png
+    attribution: from <a href="https://jenikirbyhistory.getarchive.net/amp/media/a-cargo-of-seventy-elephants-landing-from-burmah-during-the-1857-mutiny-3ff978">Metropolitan Museum of Art</a>
+authors:
+ - gbartolini
+tags:
+ - postgresql
+ - postgres
+ - pg19beta1
+summary: Participate in the PostgreSQL 19 beta program using Kubernetes and our CloudNativePG operator
+---
+[PostgreSQL 19 Beta 1 was released yesterday](https://www.postgresql.org/about/news/postgresql-19-beta-1-released-3313/)
+by the PostgreSQL Global Development Group, containing previews of all features
+that will be available when PostgreSQL 19 is made generally available.
+
+The CloudNativePG community has made available the operand container images for
+PostgreSQL 19 beta 1 in our
+[`postgres-containers` image registry](https://github.com/cloudnative-pg/postgres-containers/pkgs/container/postgresql)
+to be used with the CloudNativePG operator. The images follow our current
+naming convention — for example `19beta1-minimal-trixie` — and are not
+intended for production use.
+
+Please join us in testing the new features of PostgreSQL 19 with CloudNativePG,
+and help us diagnose and fix bugs in Postgres before the final launch.
+
+Here follows a quick example of a 3 instance Postgres 19 `Cluster` manifest to be
+deployed in your Kubernetes cluster.
+
+
+```yaml
+apiVersion: postgresql.cnpg.io/v1
+kind: Cluster
+metadata:
+ name: pg19
+
+spec:
+ imageName: ghcr.io/cloudnative-pg/postgresql:19beta1-minimal-trixie
+ instances: 3
+ storage:
+  size: 1Gi
+```
+
+Once deployed, you can easily verify the version with:
+
+```shell
+kubectl exec -ti pg19-1 -c postgres -- psql -qAt -c 'SELECT version()'
+```
+
+Returning something similar to:
+
+```console
+PostgreSQL 19beta1 (Debian 19~beta1-1.pgdg13+1) on aarch64-unknown-linux-gnu,
+  compiled by gcc (Debian 14.2.0-19) 14.2.0, 64-bit
+```
+
+If you are interested in trying CloudNativePG on your laptop with `kind`
+(Kubernetes in Docker), follow the instructions you find in the
+[Quickstart](https://cloudnative-pg.io/docs/devel/quickstart/).