Upgrade Remoting to 4.9

[agentgonzo]

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests - that demonstrates feature works or fixes the issue

Follow on from #175

[agentgonzo]

Build failure, presumably infra-related:

[2021-06-24T10:41:11.925Z] Cannot contact EC2 (aws) - Windows 2019 (i-00359c6e948511869): hudson.remoting.ChannelClosedException: Channel "hudson.remoting.Channel@416279d1:EC2 (aws) - Windows 2019 (i-00359c6e948511869)": Remote call on EC2 (aws) - Windows 2019 (i-00359c6e948511869) failed. The channel is closing down or has closed down

Can someone retrigger the build please and see if it passes this time?

[MarkEWaite]

Can someone retrigger the build please and see if it passes this time?

Launched a new build

[agentgonzo]

@slide - thanks for merging. Do you know what extra is needed to generate these images with a 4.9 tag? I can see that the CI built
the jenkins4eval/agent image from this repo, but I don't know how that gets turned into jenkins/agent. The highest tagged version is 4.7-1 (that is used in docker-inbound-agent).

What I'm ultimately after is a version of jenkins/jnlp-agent-maven that contains version 4.9 of the remoting jar.

[slide]

I need to login to the secure CI and launch a build for that tag. I'll do that today

[agentgonzo]

Ok, thanks. One that is done I'll update the inbound agents with a pr. Either over the weekend or on Monday

[agentgonzo]

@slide did you release the 4.9 image?

[slide]

Yes, I just did. The image should be pushed in the next hour or so to dockerhub

[agentgonzo]

Great, thanks!