Includes declarative pipeline support (note that you need Jenkins 2.66+ for it to work) and lots of bug fixes

The full changelog:

• Add an experimental Declarative Agent extension for Kubernetes JENKINS-41758 #127
• Implement Port mapping #165
• Support idleMinutes field in pipeline #154
• Add command liveness probe support #158
• Add toggle for node usage mode #158
• Add namespace support on PodTemplate.
• Make PodTemplate optional within pipeline JENKINS-42315
• Make Slave Jenkins connection timeout configurable #141
• Fix durable pipeline PID NumberFormatException JENKINS-42048 #157
• Don’t provision nodes if there are no PodTemplates set to usage mode Normal #171
• Refactoring add/set methods in PodTemplate #173
• Delete the build pod after we have finished with the template block #172
• Default to use the kubernetes.default.svc.cluster.local endpoint
• Do not print stack trace on ConnectException
• Upgrade kubernetes client to 2.3.1 JENKINS-44189
• Step namespace should have priority over anything else #161
• Wait for pod to exist up to 60 seconds before erroring #155
• Catch IOException on ContainerExecProc#kill
• Do not print stack trace on connection exception
• Restore random naming for pipeline managed pod templates.
• Dir context is not honored by shell step JENKINS-40925 #146
• Limit pod name to 63 characters, and change the randomly generated string #143
• Fix workingDir inheritance error #136
• Use name instead of label for the nesting stack #137
• Exception in configure page when ‘Kubernetes URL’ isn’t filled JENKINS-45282 #174
• kubectl temporary config file should work where Jenkins project contains spaces #178
• Thread/connection leak #177