Warn Java 11 users of 18 Jun 2024 end of life in weekly

[MarkEWaite]

Warn Java 11 users of 18 Jun 2024 end of life in weekly

The June 18, 2024 weekly release will require Java 17 or newer so that the upgrade from Jetty 10 to Jetty 12 has more time to complete before the eventual Oct 30, 2024 release that will require Java 17 or newer.

The administrative monitor will be activated even for those users that had previously cleared the administrative monitor because the date is part of the administrative monitor key.

Also updates the Java 11 end of life date for Java 11 users running with the long term support release.

Testing done

Verified that the correct message is displayed when run on Jenkins weekly snapshot with this change.

Verified that the correct message is displayed when run on Jenkins LTS snapshot with this change.

Proposed changelog entries

• Warn Java 11 users of the new 2024-06-18 end of life in weekly releases. This is a change from the previously announced date of 2024-09-30.

Proposed upgrade guidelines

N/A

Submitter checklist

Beta Give feedback

1. The Jira issue, if it exists, is well-described.
2. The changelog entries and upgrade guidelines are appropriate for the audience affected by the change (users or developers, depending on the change) and are in the imperative mood (see examples). Fill in the Proposed upgrade guidelines section only if there are breaking changes or changes that may require extra steps from users during upgrade.
3. There is automated testing or an explanation as to why this change has no tests.
4. New public classes, fields, and methods are annotated with @Restricted or have @since TODO Javadocs, as appropriate.
5. New deprecations are annotated with @Deprecated(since = "TODO") or @Deprecated(forRemoval = true, since = "TODO"), if applicable.
6. New or substantially changed JavaScript is not defined inline and does not call eval to ease future introduction of Content Security Policy (CSP) directives (see documentation).
7. For dependency updates, there are links to external changelogs and, if possible, full differentials.
8. For new APIs and extension points, there is a link to at least one consumer.

Before the changes are marked as ready-for-merge:

Maintainer checklist

Beta Give feedback

1. There are at least two (2) approvals for the pull request and no outstanding requests for change.
2. Conversations in the pull request are over, or it is explicit that a reviewer is not blocking the change.
3. Changelog entries in the pull request title and/or Proposed changelog entries are accurate, human-readable, and in the imperative mood.
4. Proper changelog labels are set so that the changelog can be generated automatically.
5. If the change needs additional upgrade steps from users, the upgrade-guide-needed label is set and there is a Proposed upgrade guidelines section in the pull request title (see example).
6. If it would make sense to backport the change to LTS, a Jira issue must exist, be a Bug or Improvement, and be labeled as lts-candidate to be considered (see query).

[timja]

/label ready-for-merge

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This PR is now ready for merge, after ~24 hours, we will merge it if there's no negative feedback.

Thanks!

[daniel-beck]

Given some remaining uncertainty around LTS dates it seems unnecessary to commit to another month.