Always test with container agents in CI (#46)

Containers start faster and are easier to manager

Jenkinsfile

@@ -1,9 +1,18 @@
+#!/usr/bin/env groovy
+
 /* `buildPlugin` step provided by: https://github.com/jenkins-infra/pipeline-library */
 buildPlugin(
-  // artifactCachingProxyEnabled: true,
+  // Container agents start faster and are easier to administer
+  useContainerAgent: true,
+  // Show failures on all configurations
+  failFast: false,
+  // Opt-in to the Artifact Caching Proxy, to be removed when it will be in opt-out.
+  // See https://github.com/jenkins-infra/helpdesk/issues/2752 for more details and updates.
+  artifactCachingProxyEnabled: true,
+  // Test Java 8 with default Jenkins version, Java 11 with a recent LTS, Java 17 even more recent
   configurations: [
-    [platform: 'linux',   jdk: '17', jenkins: '2.376'],
-    [platform: 'linux',   jdk: '11', jenkins: '2.361.3'],
+    [platform: 'linux',   jdk: '17', jenkins: '2.375'],
+    [platform: 'linux',   jdk: '11', jenkins: '2.361.4'],
     [platform: 'windows', jdk:  '8']
   ]
 )