chore(pom): Use recommended core version 2.462.3, and Java 11.

[gounthar]

Hello proxmox developers! 👋

This is an automated pull request created by the Jenkins Plugin Modernizer tool. The tool has applied the following recipes to modernize the plugin:

Upgrade to the latest recommended core version and ensure the BOM matches the core version

io.jenkins.tools.pluginmodernizer.UpgradeToRecommendCoreVersion

Upgrade to the latest recommended core version and ensure the BOM matches the core version.

Why is this important?

Jenkins plugins declare a minimum supported Jenkins version.
The minimum Jenkins version is a useful way for plugin developers to indicate the range of Jenkins versions they are willing to support and test.
See the developer documentation to learn more about the recommended minimum Jenkins version.
The current minimum required Jenkins version is 2.462.3, which is why this pull request has been made.

If the plugin is already using the plugin bill of materials, then the bill of materials also needs to be updated with the matching artifactId for the minimum required Jenkins version.

I can't see any change to the Jenkins version, how come?

This means your plugin POM was already using the 2.462.3 version but still required a few adjustments.

The checks fail, why?

For security reasons, the Jenkins infrastructure does not execute Jenkinsfiles proposed in pull requests.
Instead, it builds the code using the Jenkinsfile from the default branch.

In this case, the existing Jenkinsfile specifies Java 8, not Java 11, which is causing the check to fail.
To resolve this,
a maintainer can replay the failed build
by substituting the current Jenkinsfile content with our proposed changes using the "replay the build"
feature in Jenkins.

Please let us know if you need any assistance with this process.

Thanks for taking the time to review this PR.
🙏