README: Update releases

Signed-off-by: André Martins <andre@cilium.io>

Author: aanm

README.rst

@@ -95,7 +95,7 @@ corresponding image pull tags and their release notes where applicable:
 +----------------------------------------------------------------------------+------------+-----------------------------------------+---------------------------------------------------------------------------------+
 | `main <https://github.com/cilium/cilium/commits/main>`__                   | daily      | ``quay.io/cilium/cilium-ci:latest``     | N/A                                                                             |
 +----------------------------------------------------------------------------+------------+-----------------------------------------+---------------------------------------------------------------------------------+
-| `v1.20.0-pre.0 <https://github.com/cilium/cilium/commits/v1.20.0-pre.0>`__ | 2026-03-02 | ``quay.io/cilium/cilium:v1.20.0-pre.0`` | `Release Notes <https://github.com/cilium/cilium/releases/tag/v1.20.0-pre.0>`__ |
+| `v1.20.0-pre.1 <https://github.com/cilium/cilium/commits/v1.20.0-pre.1>`__ | 2026-04-01 | ``quay.io/cilium/cilium:v1.20.0-pre.1`` | `Release Notes <https://github.com/cilium/cilium/releases/tag/v1.20.0-pre.1>`__ |
 +----------------------------------------------------------------------------+------------+-----------------------------------------+---------------------------------------------------------------------------------+
 
 Functionality Overview