This is a follow-up to JENKINS-20679 and a placeholder for the https://github.com/jenkinsci/jenkins/pull/3016 created by danielbeck against the Jenkins core.

Acceptance criteria:

• "Minimum-Java-Version" manifest entry is checked from the update center. It may be missing
• Update listing shows showing warnings for plugin updates which are not compatible with the current Java version

Out of scope (kept for later ideating):

• For LTS versions Jenkins queries the update center and offer the latest compatible plugin version instead (if possible)