[Platform CI] Jenkins doesn't start anymore due to kubernetes-credentials-provider plugin

The Platform Jenkins doesn't start anymore due to a recent release of the kubernetes-credentials-provider plugin which requires a more recent version of the kubernetes-client-api plugin than the one we install due to NXBT-3622.

As the Jenkins issue linked to NXBT-3622 is not fixed we can't update the kubernetes-client-api plugin, we need to fix the kubernetes-credentials-provider plugin to 0.20 version.

Error logs:

❯ kubectl -n platform logs -f jenkins-0 -c init
disable Setup Wizard
remove all plugins from shared volume
download plugins
Plugin prerequisite not met:
Plugin kubernetes-credentials-provider:0.22 depends on kubernetes-client-api:5.12.1-187.v577c3e368fb_6, but there is an older version defined on the top level - kubernetes-client-api:5.4.1

Culprit release: https://github.com/jenkinsci/kubernetes-credentials-provider-plugin/releases/tag/kubernetes-credentials-provider-0.21