[ci.jenkins.io] General availability of Maven 3.9.4

[Damien Duportal]

Hi folks,

As per https://github.com/jenkins-infra/helpdesk/issues/3708, Maven 3.9.4 is now deployed to the platform and is the default Maven version.

Feel free to contact us if this upgrade is doing any harm on your plugins or projects.

For the infra team,

Damien Duportal