Update jenkins base image to include java 11

[ma-schmidt-de]

Building the docker image of the Spring Boot app leads to the following compile error because jenkins/jenkins:2.225 only includes java8:

Task :compileJava FAILED FAILURE: Build failed with an exception. What went wrong: Execution failed for task ':compileJava'. Could not target platform: 'Java SE 11' using tool chain: 'JDK 8 (1.8)'.

I was following instructions on your post: https://tomgregory.com/building-a-spring-boot-application-in-docker-and-jenkins/?unapproved=89&moderation-hash=04cac9c3530f9d2c399d5216eb3e6605#comment-89