Require Java 11 at runtime, build on Java 21/25

[melissalinkert]

See https://www.openmicroscopy.org/2026/03/24/end-of-java-8-support.html. Similar to ome/ome-metakit#33.

[sbesson]

The proposed changes update the build system to use the --release option of the Java compiler to generate files compatible with Java 11 and later. This is consistent with the message published on the OME website.

Here and in associated PRs, the README should also be updated to communicate the minimal requirement.

Regarding the testing matrix, an open question is whether the build & tests should be executed against the whole range of supported LTS versions (11, 17, 21, 25) or a relevant subset of these versions. Could you comment on why you settled on 21 & 25 for the GitHub Actions?

In addition to the above, this includes updates to the workflow to handle upcoming GitHub runner deprecations -https://github.blog/changelog/2025-10-28-upcoming-deprecation-of-codeql-action-v3/ https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/ and removes build warnings 💯

[melissalinkert]

Dropping Java 11 from the matrix was in line with glencoesoftware/bioformats2raw#294, but that probably isn't necessary here since we're not using Gradle in any of the components. In dropping Java 17, I think I was thinking that the last 2 sentences of https://www.openmicroscopy.org/2026/03/24/end-of-java-8-support.html imply that Java 21 is the recommended version. c723c43 restores both 11 and 17 to the matrix - if we're happy with that, I'll apply to the other open PRs like this.

I think I caught README changes in most of the other components, but missed this one because it previously stated Java 1.9+ instead of Java 1.8+ (so git grep 8 didn't catch).

[sbesson]

Thank you @melissalinkert. Happy with the current approach, feel free to update all the related PRs. As discussed at the weekly Formats meeting, approving but holding off on the merging of these PRs for a few weeks.