[Jenkins Infra] Upgrade of Kubernetes 1.26 in Azure

[Damien Duportal]

As per https://status.jenkins.io/, the Jenkins infrastructure team is running a cluster upgrade of AKS to Kubernetes 1.26.

We are starting the upgrade now: expect outages with the log-in/log-out on all "*.jenkins.io" services during the next hour due to LDAP restart.

The incremental publisher service is also in the operation scope: please avoid releasing incremental plugin versions and trigger a new PR build (with an empty commit) once the operation is finished to successfully publish your incremental releases.

Stéphane and Damien, for the Jenkins Infra team

[Damien Duportal]

The upgrade operation is now finished.

It went successfully, with a measured 6 min outage on the LDAP and 2 min on the incremental publisher.

The platform is now in nominal condition.

Damien