[ci.jenkins.io] Updated Maven settings.xml

[Damien Duportal]

Hi dear contributors,

for information, as part of the bandwidth reduction effort in our Artifactory instance (ref. https://github.com/jenkins-infra/helpdesk/issues/3599), the Jenkins infra team have deployed an updated `settings.xml` for the ci.jenkins.io agents.

This updated version features a new default profile which sets up the list of "pluginRepositories" as you can see in https://github.com/jenkins-infra/jenkins-infra/pull/3041/files.

There should be no impact BUT as usual if anything unusual happens in your build (in the dependency resolutions phases), please let us now by opening a new issue in github.com/jenkins-infra/helpdesk!

Cheers

Damien Duportal