Update Ubuntu image to eclipse-temurin:21.0.8_9-jdk-noble

The base image for Ubuntu is now Ubuntu 24.04.3 LTS.

Change-Id: Ic08be0544ccfee6444f2b0d8e5ea942a716b9314

ubuntu/24/Dockerfile

diff --git a/ubuntu/24/Dockerfile b/ubuntu/24/Dockerfile
index 3bb3236..1cc3eab 100644
--- a/ubuntu/24/Dockerfile
+++ b/ubuntu/24/Dockerfile
@@ -1,4 +1,4 @@
-FROM eclipse-temurin:21.0.6_7-jdk-noble
+FROM eclipse-temurin:21.0.8_9-jdk-noble
 LABEL org.opencontainers.image.authors="luca.milanesio@gmail.com"
 
 # Add Gerrit packages repository