Bump base image os to ubuntu 26.04 (#17)

(cherry picked from commit 7bc0c9c)

Author: houssemexo26

Dockerfile

@@ -6,7 +6,7 @@
 #           docker run -d --name=exo -p 80:8080 exoplatform/chat-server
 
 # ----- build step 1
-FROM  exoplatform/jdk:21-ubuntu-2404 AS install
+FROM  exoplatform/jdk:21-ubuntu-2604 AS install
 
 ARG CHAT_SERVER_VERSION=7.2.0-20260423
 
@@ -18,7 +18,7 @@ RUN chmod u+x /download.sh && sync && /download.sh
 RUN cd /usr/local && unzip /chatserver.zip && mv chat-server-standalone-${CHAT_SERVER_VERSION} chat-server
 
 # ----- build step 2
-FROM  exoplatform/jdk:17-ubuntu-2204
+FROM  exoplatform/jdk:21-ubuntu-2604
 LABEL maintainer="eXo Platform <docker@exoplatform.com>"
 
 # Install the needed packages